v>EPA
            United States
            Environmental Protection
            Agency
                Environmental Research
                Laboratory
                Athens GA 30605
EPA-600 1 78 070
December 1978
            Research and Development
    Schistosomiasis in
    Rural Egypt

    A Report of U.S.-
    Egyptian River
    Nile and Lake Nasser
    Research Project
  EP 600/1
  73-070
•^

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                RESEARCH REPORTING SERIES

Research reports of the Office of Research and Development, U S Environmental
Protection Agency, have been grouped into nine series These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology Elimination of traditional  grouping  was consciously
planned to foster technology transfer and a maximum interface in related fields
The nine series are

      1   Environmental Health  Effects Research
      2   Environmental Protection Technology
      3   Ecological Research
      4   Environmental Monitoring
      5   Socioeconomic Environmental Studies
      6   Scientific and Technical Assessment Reports (STAR)
      7   Interagency Energy-Environment Research and Development
      8   'Special" Reports
      9   Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL HEALTH EFFECTS RE-
SEARCH series  This senes describes projects and studies relating to the toler-
ances of man for unhea'thful  substances or conditions This work is generally
assessed from a medical  viewpoint including pnysio'ogicai o> psychologies
studies  In addition to toxicology and other medical specialities, study areas in-
clude biomedical  instrumentation  and hea'fh research fecnmques utilizing ani-
mals — but always with intended  application to human health measures
 This document is available to the public through the National Technical Informa-
 tion Service Springfield, Virginia  22161

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                                     EPA-600/1-78-070
                                     December 1978
       SCHISTOSOMIASIS IN 8UHAL  EGYPT
    A Report of 0. S,-Egyptian River  Nile
      and Lake Nasser Research Project.
                     by
              F. DeWolfe Miller
               Mohamad Hussein
               Khalil H. Mancy
              Morton S. Hilbert
         The University of Michigan
           School of Public Health
      Ann Arbor, Michigan, U.S.A.  '48109
                     and
        The University of Alexandria
       High Institute of Public  Health
           Alexandria, A.E. Egypt-
Special Foreign Currency Project No.  03-542-1

               Project Officer

           Walter M. Sanders, III
      Environmental Research Laboratory
        Athens, Georgia, U.S.A. 30605
      ENVIRONMENTAL HESFARCH LABORATORY
     OFFICE OF RESEARCH AND DEVELOPMENT
    U.S. ENVIRONMENTAL PfiOTECTION AGENCY
            Athens, Georgia 30635

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                                 DISCLAIMER
      This report has been reviewed  by the  Environmental Research Laboratory,
U.S. Environmental  Protection Agency,  Athens,  Georgia,  and approved for
publication.   Approval  does not signify that the  contents necessarily reflect
the views and policies  of the U.S.  Environmental  Protection Agency, nor does
mention of trade names  or commercial  products  constitute endorsement or
recommendation for use.

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                          FOREWORD
      After centuries of  annual  flooding  and drought, the
constuction of the Aswan High Dam has povided effective flow
control to the River Nile  as it enters the fertile Egyptian
Nile Valley.  The  dam  has  resulted  in  the production of
hydroelectric  power   for   municipal,   agricultural,  and
industrial use,  and the continuous availability of water has
increased agricultural productivity.    Optimum benefits from
a  project  of  this  magnitude  cannot  be  fully realized,
however,  until    the   major  environmental,  agricultural,
social,  economic,  and  public  health  impacts  have  been
incorporated  into   strategies   for   managing  the  water
resources within the basin.  Tn 1975, the U.S. Environmental
Protection Agency and the  Ford  Foundation began support of
a 5-year,  multifaceted  research  program  conducted by the
Egyptian Academy of  Scientific  Research and Technology and
related  institutions  and  the  University  of  Michigan to
provide  the  information  needed  for  comprehensive  water
quality management in the Nile Valley.

      Although  the  project   addresses   issues  of  vital
importance to Egypt, the  knowledge  gained  also will be of
significant benefit  to  the  general  scientific community.
For example, water resources management models developed for
the Nile Basin can be  applied  to  some river basins in the
United States.

      This report, the first of  a series growing out of the
public  health   portion   of   the  U. S.-Egyptian  project,
describes   a   research   study   of   the   prevalence  of
schistosofflisasis--a chronic disease  of  the liver, bladder,
and lunqs--followiny the  regulation  of  water  flow in the
river, canals, and  drainage  ditches  brought  about by the
dam.

                                     David W. Duttweiler
                                     Director
                                     Environmental  Research
                                     Laboratory
                                     Athens, Georgia
                             m

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                           PREFACE
      The Aswan High Dam was  built for the purpose of water
storage,  river   flow   control   and  hydroelectric  power
production.  The  fulfillment  of  these  goals  is of vital
inportance   for   Egypt's   agricultural   and   industrial
development programs.   This can be easily realized since the
River Mile constitutes 90%  of Egypt's fresh water resources
and the  present  population  of  38  million people inhabit
approximately four  percent  of  the  land  and  the rest is
barren desert.   Nevertheless, since its inception, the Aswan
High Dam has  been  under  unprecedent  attacks  in the news
oedia and the scientific literature.  It has been blamed for
causing serious  ecological  perturbation  which resulted in
reducing the fish population  in the Mediterranean, lowering
the fertility of  the  Nile  Valley, and narkedly increasing
schistosomiasis in Egypt.  In  contrast to the above claims,
our study  indicated  a  marked  decline  in schistosomiasis
prevalence in rural Egyp^ over the past forty years.

      These  research  findings   are   the   outcome  of  a
comprehensive ongoing project dedicated  to the study of the
River  Nile  and  the  impacts  of  the  Aswan  High  Data on
multipurpose   river   uses.    This   includes  irrigation,
community water supply, fishery, recreation, transportation,
etc.  The aim of  this  project  is  to provide the decision
makers  in   Sgypt   with   river   management  alternatives
compatible with government  goals  for economic developaent.
This includes the  assessment  of trade-offs and predictions
of  the   outcome   of   each   river  resources  manageaent
alternative.  This is a  joint  project between the Egyptian
Academy  of  Scientific  Research  and  Technology  and  the
University of Michigan.  The technical and financial support
of  the  U.S.  Environmental  Protection  Agency,  the  Ford
Foundation, and the World Bank is highly appreciated.

                             Khalil H. Mancy
                             Principal Investigator
                             July 17, 1978
                              IV

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                          ABSTRACT

      The prevalence of  schistosoiaiasis  in  Egypt has been
high for a long  time  as  a result of widespread irrigation
schemes.  The possible effect of the proposed Aswan High Dam
and the resulting formation of Lake Nasser on the prevalence
of schistosoffliasis created a  controversy in both the public
and scientific press.  It was speculated that the Aswan High
Dan and related  irrigation  development would contribute to
an increase in schistosotniasis.

      The objectives of this  s*udy  were to provide current
information on the  prevalence of schistosoraiasis throughout
Egypt,  to   establish    trends   in   the   prevalence  of
schistosomiasis  in order  to  shed  light  on the potential
changes caused  by  the  Aswan  High  Dam,  and to determine
correlations  between  certain  environmental  variables and
schistosomiasis prevalence.

      This research was divided into two studies.  The first
was a field study in  thirty-three villages located in Upper
Egypt, Upper-Middle  Egypt,  and  the  Nile  Delta.   In the
second investigation, eight  villages  were  selected in the
resettled  Nubian  population  in  Kozn  Ombo.   The sampling
methodology used insured  that  the probability of selection
could  be  calculated  for  any  given  person  sampled.  To
evaluate  these  findings,   extensive  historical  data  on
schistosoffliasis  prevalence  in   Egypt  were  compiled  and
assessed for factors of comparability.

      The overall  prevalence  of schistosomiasis, corrected
for differences  in  sampling  fraction  and  age,  in seven
villages in the north central  Nile  Delta was 42.1%, in six
villages in Upper-Middle Egypt  (in  the governorate of Beni
Suef) the overall prevalence  was  26.7%, and in the sixteen
villages in the  jovernorate  of  Aswan,  the prevalence was
4.1^.   Prevalence  was   invariably   higher  in  the  male
adolescents with the  differential  between sexes increasing
from north to south.  The prevalence was significantly lower
in *-hose villagers who obtained  water for domestic use froa
protected supplies.   Villages in  Upper Egypt located on dry
barren ground had a  much  lower  prevalence, by five times,
than  the  villages  surrounded  by  cultivated  lands.  The
effect of  population  growth  and  migration  from rural to
urban areas on  schistosomiasis  prevalence and distribution
was discussed.

      Results based on  trend  analysis  of current and past
data indicated a  strong  decline  in  overall prevalence of
schistosoraaisis in the rural  population over the past forty

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years.   The data did  not  show  an  increase in the overall
prevalence of schistosomiasis  following the construction of
the Aswan High Dam.   The Nubian population also experienced
a decrease in prevalence following relocation, from 15.2% to
7.2%, with some villages benefiting more than others.

      Environmental conditions were  also correlated against
schistosoiaiasis  prevalence   and   additional   aspects  of
transmission  were  discussed.    It   is   hoped  that  the
information  presented  here  on   the  natural  history  of
schistosomiasis  transmission  in  Egypt  will  aid  in  the
control and eradication of this disease.

      This research was implemented  through the River Nile-
Lake Nasser project, a joint University of Michigan-Egyptian
Academy of Scientific  Research  and Technology project, and
funded by the U.S.   Environmental  Protection Agency and the
World Dank.

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                      TABLE OF CONTENTS


FOPEPORD	     iii

PREFACE	       iv

ABSTRACT	       ir

LIST OF TABLES	       il

LIST OF FIGURES.	     xiii

ACKNOWLEDGEdENTS .......... 	  .      xvi

CHAPTER

   T.  INTRODUCTION	       1
          The Disease: Schistosomiasis .......        1
          Life Cycle of Schistosomiasis	       2
          Tite Setting: Egypt	       3
          Dams, Irrigation/ and Schistosoiaiasis.  .  .       4
          The Controversy	       10
          Research Objectives. ...........       11

  II.  REVIEW OF LITERATURE	       13
          Introduction . 	 .........       13
          Background Work on the  Prevalence of
          Schistosomiasis. ........ 	       14
          Schistosomiasis in Egypt .........       15
               Country Wide Prevalence Surveys ...       16
               Schistosomiasis in the Nile Delta  .  .       24
               Schistosoraiasis in Upper-Middle Egypt       38
               Schistosomiasis in Uppe'r Egypt. ...       46
               Schistosomiasis in Nubia	       50
               Schistosomiasis in Lake Nasser. ...       56
               Schistosomiasis in the Desert and
               Reclamation Sectors .........       59
               Schistosomiasis in Egypt;  A Summary.       60
          Irrigation Expansion and the Aswan High
          Dam	       61
          Environmental Health Conditions in Egypt  .       66

 III.  MATERIALS. AND METHODS	       77
          Description of the "Downstream Study".  .  .       77
          Description of the "Nubian Study"	       78
          Hypotheses	       79
          Data Acquisition	       80
          Specific Data Collected.	       81
          Selection of Field Survey Sites. .....       82
          Data Collection Teams.  ..........       86
          Review of Facilities and Preparation of
          Materials	       86
          Preservation of Stool and Urine Specimens.       89
                            vi i

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          Examination of Stool and Orine Specimens .       90
          Selection of the Sample Population ....       92
          Examination of the Environment and the
          Population ..... 	 ......       94
          Data Management and Analysis	  .       97
               Adjustment Scheme ..........       99

  IV.   RESULTS	      100

          Results of the Downstream Study.  .....      100
               Selection of the Sample and Response.      100
               Age-Sex Distribution of the Sample.  .      101
               Overall Prevalence of Schistosoniasis
               in the Study Areas. .........      101
               Age Sex Distribution of
               Schistosomiasis in the Study Areas.  .      114
               Environmental Aspects of the
               Downstream Study Sites, .......      120
          Results of the Resettled Nubian Study. .  .      130
               Selection of the Saaple and Response.      130
               Age-Sex Distribution of the Nubian
               Sample. ........ 	      130
               Overall Prevalence of S..hae matobiua
               in the Nubian Sample. ........      130
               Environmental Aspects of New Nubia.  .      132

   V.   DISCUSSION AND CONCLUSIONS.	      142
          The Downstream Study: General Aspects. .  .      142
          Water Supply and Schistosomiasis .....      146
          Distribution of J5_. ffiansoni. and the AHD ,  .      147
          General Estimates of Schistosomiasis . .  .      148
          Secular Trends in Schistosomiasis. ....      151
          Population Changes and Schistosomiasis .  .      156
          The Nubian Study	      159

REFERENCES ... 	 .....      163

Appendix I.....................      174

Appendix II. ....................      175

Appendix III ......... 	 ......     190

Apnendix IV.	      194
                            vm

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                  LIST OF TABLES

                                                   Page

1.  Effects of conversion from basin irrigation
to perennial irrigation in Kom Ombo, Upper
Egypt ......... ............       7

2.  Summary of prevalence surveys for
bilharziasis in Eqypt, by area, year, and
author.  ........... ..... ....       15

3.  Surveys of bilharziasis completed between
1866 arid 1924 .......... ........       17

4.  Prevalence of bilarziasis in the Nile Delta
in 1935 ...................  .       18

5.  Prevalence of bilharTiiasis in areas south
of Cairo in 1935. After M. A. Azira  (1935) ...       19

6.  Comparison of results of two surveys, Scott
(1935)  and EflPH  (1955) for schistosomiasis in
different regions of  Egypt. ..........       25

7,  Prevalence of urinary schistosomiasis by
age and sex aaonq 60,197 persons surveyed in 23
villages iu different  locations in  Egypt in
1955 by the EflPH. .... ...........       32

8.  Corrected estimated prevalence  of
bilharziasis in the Egypt-49 project area by
division. ...................       35

9.  Prevalence of schistosoraiasis in Kafr El
Sheikh, Nile Delta ........ . ......       37

10.  Percent prevalence of schist.osomi.asis in
the northwestern Mile  Delta by selected years..       39

11.  Age-specific prevalence of S._  haeaatobiua
in the Fayoum, 1949 ..............       41
12.  A summary of results taken from a survey
for S^_ haematobium in the area between Assyut
and Aswan in 1972 by Dazo Biles  (1972) .....       49

11.  The percent prevalence of 5,_ haematobiua
in Nubia, 1958. .  . ....... 7 ......       53

14.  Age-specific prevalence of S_._ haematobiua ,
Nubia, 1958 .......... .."..... 7 .       54
                          IX

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15.  Distribution of individuals who submitted
urine and/or stool specimens by age, sex, and
locality (Tribe), Nubia, Egypt, U.A.H.,  1963.
After Zawahry (196U)	      55

16.  Percent prevalence of bilharziasis by age
and sex; Nubia,  Egypt, 17. A.F., 1963	      57

17.  Percent prevalence of bilharziasis by
locality (tribe) and sex; Nubia, Egypt. . , . .      58

18.  The status of irrigation schemes in
Hpper-Middle Egypt and Upper Egypt by year. . .      63

19.  Conversion to "permanent" irrigation by
year in selected governorates .........      65

23.  Aggregate cropped surface  ('000 feddans) .      67

21.  Distribution of examined population by
source of water supply	      71

22.  Distribution of examined population by
type of housing..	      71

?3.  Hater and waste-water facilities in Opper-
Wiidle Egypt in 1975	      72

24.  Tribe, location, village, and number
of families selected in Nubia, 1960 ......      73

25.  Housing characteristics. Old Nubia, 1960  .      74

26.  Water supply and lighting in Old Nubia,
1960.	      75

27.  The pattern of selection and response
in <-he Downstream study sites,. ........     102

28.  The number of persons attending the
Downstream study by age and area. .......     104

29.  The number of persons examined in
Kafr El Sheikh by age and site	     105

30.  The number of persons examined in
the Beni Suef study area by age and by study
site......................     106

31.  The number of persons examined in the
Aswan area by age and by site .........     107

32.  The overall prevalence of  schistosomiasis
in the Kafr El Sheikh study area.	     109

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33.  The overall prevalence of schistosomiasis
by study site in the Kafr El Sheikh study  area.      111

34.  Prevalence of S,_ haematgbium in the  Beni
Suef study sites. Upper-Hiddle Egypt.  .....      112

35.  Overall prevalence of S._ h a em a to bi urn  in
the study sites of the Aswan governorate,  ...      114

36.  Results of the subsample in Bimban,  Aswan.      115

37.  The number examined and percent positive
by age and sex in the Kafr El Sheikh area  for
all those infected with both S._ h_ajs m a^to bi urn and
	 	 and infected with either or both
species..	      118

38.  Age-sex distribution of S_. haematobium
infection in the sample from the Beni Suef
area.	      120

?Q.  The number examined and the percent
positive by age and sex for 5. hag-gat obium in
the Aswan study area excluding the results from
Bimban  (10)..  	      121

40.  The number examined and the percent
positive by age and sex for S.. haeniatobium in
the Bioiban (10)  subsample	      123

41.  The prevalence of schistosomiasis and the
distribution of persons per standpipe in the
Kafr El Sheikh study area.. ..........      124

42.  The number of persons in the sample from
Kafr El Sheikh by water source and use. ....      124

43.  The percent prevalence of S._ haeaiajtobiiim
bv source and use of water supply from Kafr El
Sheikh study area.. ........ 	      126

44.  The percent prevalence of £>._ roan_son_i by
source and use of water supply in the sample
     Kafr El Sheikh	      128
45.  The prevalence of schistosomiasis and  the
distribution of persons per standpipe in  the
Beni Suef study area.	      128

46.  The number of persons in the sample  from
Beni Suef by water source and use.. ......      129

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47.  The percent prevalence of S._ haematobjLum
by source and use of water supply in the sample
from Beni Suef. .. ..............     129

48,  The number of persons per standpipe by
study site in Aswan.. .............     132

49.  Percentage of homes with latrines  and the
relationship to schistosomiasis prevalence in
the Aswan study sites.. .. ....... ...     133

SO,  The pattern of selection and response in
the Nubian sample ..... ....... ...     135

51.  The. number examined and the percent
positive by age and sex for _§_. haemat,obium in
the Nubian sample,. ..............     137

52.  The percent prevalence of §.._ haematgbiua
in the Nubian sample by study site .......     140
53.  Estimated prevalences for the different
Downstream study areas based on special
assumptions stated in the text. ........      150

54.  Nile Delta:  Percent prevalence of
schistosomiasis for selected years. ......      152

55.  Upper-Middle Egypt  percent prevalence of
Si b§.§Ml2kilil! by selected years. .......      154

56.  Table showing the results of certain
assumptions made on the prevalence of
schistosomiasis in respect to population
changes in Egypt. ...............      157

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                  LIST OF FIGCJRES

                                                    Page

1.  A Map of Egypt in the 1930 's ...... .  .       5

2.  A map of Egypt in three parts, divided
roughly into Lower Egypt  (Nile Delta) , Upper-
Middle Egypt, and Upper Egypt ...... ....       6

3.  A map of Egypt taken from Scott  (1937),
that shows the prevalence per  100 of
§._ haeaat^obiuin among persons examined at EMPH
traveling hospitals during the 1930's.. ....       21

4.  A map of Egypt showing the prevalence per
100 o f S_i haematohiuin among rural persons
examined at their homes by Scott  (1937) .....       22

5.  Two maps of the Nile Delta showing the
percent prevalence of £>._ mansoni during the
1930's. .... .......... . .....       23

6.  The prevalence of schistosomiasis in four
surveys.. .... ........... ....       30

7,  The distribution of schistosomiasis by age
in the Egypt-49 project area and in its four
divisions.. ........ ..........       34
8.   This graph was plotted after data obtained
from the EMH  (1975) for the Fayoura governorate
schistosomiasis control project.. ......
9.   The age-sex specific prevalence of
S._ h.afc_matobi.uji in selected sites of the Beni
Suef governorate in 1972. ...........       45

10.  This is a photographic reproduction made
by a LANDSAT satellite of Upper-Middle and
Upper Egypt ........... ........       HI
11.  This is a map of +he Kom Ombo area showing
the resettlement pattern of the Nubian tribes..      52
12.  A "floating pump station" in Qena
13.  The relationship between population growth
and agricultural expansion. ..........      68

^ 4.  This is a sketch nap of the Kom Orabo area
showing the distribution of health units and
centers .......... ...........      85

                         x i i i

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15.  The age distribution by study site in the
Kafr El Sheikh study area	 .      103

16.  The age distribution by study site in the
Beni Suef study area.	      108

17.  The age distribution by study site in the
Aswan study area	      110

18.  The adjusted age distribution from the
Kafr El Sheikh sMidy area compared to the age
distribution for this same rural area according
to the 1960 census data  (CAPMAS, 1960) .....      113

19.  The adjusted age distribution from the
Beni Suef study area compared to census data
for this area  (CAPMAS, 1960)	      116

2C.  The adjusted age distribution from the
Aswan study area compared to census data for
this same region  (CAPMAS, 1960)	      117

21.  The adjusted age-sex prevalence
distribution for schistosooiiasis for  all study
sites combined in the Kafr Kl Sheikh  study
area	      122

22.  The adjusted age-sex prevalence
distrioution for S._ haemaJ:objLujB infections for
all study sites in the Kafr El  Sheikh study
area	      125

23.  The adjusted age-sex prevalence
distribution for S_^ JL§iL§onJ. infections for all
study sites in the Kafr  El Sheikh  study area, .      127

24.  The adjusted age-sex prevalence
distribution for infection  with both  species
for all study  sites  in the Kafr El Sheikh study
area.....  	 ........      131

25.  The adjusted age prevalence distribution
for those infected with  both species  and for
those infected with  either  or  both species. . .      134

26.  The adjusted aae-sex prevalence
distributon for S_z liaejnat_obiujn  infections in
the study sites from the Beni  Suef study area..      136

27.  The adjusted age-sex distribution  for
JLt h.a fe mat obi urn infections in the study  sites
from the Aswan study area.. ..........      138
                          xiv

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28.  The age distribution by study site in the
Nubian sample	     139

29.  The adjusted age prevalence distributon
for S^ haematQbium infections in the Nubian
sample. ....................     141
                          xv

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                      ACKNOWLEDGEMENTS
      This is a very important  section.  The size and scope
of the activity  necessary  to  compile  data on over 15,000
persons living in 41 rural  Egyptian villages located at the
extremes of the Nile Valley  in  Egypt is understated in the
main body of this thesis.  An undertaking of this magnitude,
which '-ook me  to  Egyp*-  for  almost three years, obviously
required the  participation  of  many  others.   So many, in
fact, that  as  I  write  this  section  a  streata of faces,
persons, friends that I met and  who helped me in many, many
ways comes  to  my  mind  and  shape  not  -just  a series of
repeated encounters, hut an incredible story about some very
reassuring aspects of  human  relationships.   The format of
this section, however, limits my story to essential aspects.
This is not to say that the many that are not mentioned here
because of  spatial  limitations  have  been  forgotten, but
rather, to whoa I will be forever grateful.

      Foremost  in  making  this  study  a  reality  was  my
Egyptian mentor.  Dr.  Mohamad  Hussein,  Dean  of  the High
Institute of Public Health  at the University of Alexandria,
Alexandria, Egypt.  Aside from the  many details which I was
totally unable to acquire and which Dr. Hussein acquired for
me, such as various governmental approvals,  Dr. Hussein was
unfailing  in  his  support,  patience,  and  kindness.  His
technical steerage was   invariably  accurate and vital.  The
technical and cultural  blunders  I  would have made without
his  assistance  would  have  circumvented  any  measure  of
progress or success  that  I  might  have made otherwise.  I
consider myself fortunate that T was able to study and learn
under the direction of Dr. Hussein.

      Inadeguate as it is  as  an expression of gratitude, a
list has been  prepared  of  special  persons in Egypt whose
help has been invaluable.

      Dr. Baha Hashem, Director-Gt-neral of Pural Health, the
      Egyptian Ministry of  Health   (EMH).   Assigned to the
      project  as  representative   team   leader  from  the
      Ministry,  Dr.   Hashem's   help   in   obtaining  the
      cooperation of the rural health staff was invaluable.

      Dr.  Ahmad  Nagaty,   Vice-Director-General  of  Rural
      Health, EMH.  Dr.  Naqaty  was very helpful with advice
      on methodology and transportation.

      Dr. Lotfi  Abdel   Khalek,  Director-General of Health,
      Beni Suef.  Dr. Khalek1s enthusiasm for field  work was
                             XVT

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      unsurpassed in the Deni Suef  government.  To him I am
      thankful for the success of the project in that area.

      Dr.  Abdel Sarnie  Omran  El-Sherif, Director-General of
      Health, Aswan.  Dr.  Fl-Sheri^s  support in Aswan was
      very helpful.   I  thank  him  for the many informative
      hours spent together.

      Dr.  Mahmoud  Yasin,  Vice-Director-General  of Health,
      Aswan.   Or. Yasin's  support  in the field, frequently
      under difficult conditions, and his consistent follow-
      up on the  many  aspects  of  the  study in Aswan were
      especially appreciated.

      Dr.  Madowi, Director-General of Kafr El Sheikh.

      Dr.   Sashida  Barakat,  Parasitologist,  University of
      Alexandria,  Under  her  direction  the  huge  task of
      analyzing the   thousands  of  specimens was completed.
      Hard-working and extremely  knowledgeable, Dr. Rashida
      epitomizes, to roe, the modern Egyptian woman.

      Dr.    Ibrahim    Farag,   Systems   specialist,   Cairo
      riniversity Computing Center.

      Dr.   Noshy  Mansour,  Parasitologist,  Naval  American
      Medical Research Unit  (NASRU-3),  Cairo.  Dr. Mansour
      was very  helpful  with  the  preparation  of the MIFC
      nrescrvation technique,  and  provided  a mechanism of
      evaluating parasitological results.

      Dr.   Gene   Hagashi,   Immunologist,  NAMRU-3,  Cairo.
      Dr.  Hagashi was  extremely  helpful  and supportive in
      the development of many aspects of the field study.

      Dr.   Merrill  Shut.t,  Medical  Officer,  U.S. Embassy,
      Cairo.

      Dr.   El-Mumtaz  Mubarak,  Under-Secretary  for Endenic
      Diseases, EMH, Cairo.
      A very special thanks  to  Dr.  and  Mrs. G. tfhite for
their pncouragement thronghou*  this  research.  Dr. White's
assistance in providing a  mechanism for acquiring funds for
the analysis of the data  at  the University of Michigan was
greatly appreciated.  In this  respect  I also wish to thank
fr. C.  Gunnerson  of  * he  World  Bank  for  his support and
understanding  in  the  preparation  of  this  document.   I
appreciate the help of the  staff at the Egyptian Academy of
Scientic Research  and  Technology  under  the  direction of
Dr. «.  Hafez.

      There  were,  as   mentioned,   over  15,000  Egyptian
                             xv ii

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villagers to whom I will be forever frustrated in expressing
my appreciation.  I can only  hope  that the results of this
study will  in  soiae  way  help  control  and eradicate this
parasitic  infection   that   is   so   prevalent  in  their
population.

      Counterpart to all  those  in  Egypt  are my committee
members  here  at  the  University  of  Michigan.  Professor
Morton S. Hilbert was  instrumental  in guiding me into this
aspect  of  environmental   health.    His  continued  open-
mindedness and support, have been of the greatest assistance.
Co-chairing  my   committee   with   Professor  Hilbert  was
Professor Khalil H. flancy.   Dr.  nancy  is a most respected
teacher and friend.  I am  most grateful to Dr. Arnold Monto
for his patience in reviewing  many drafts and whose intense
involvement in the collection and analysis of the field data
was particularly insightful.  I also  wish to thank Dr. Rolf
Deininger for his assistance in computer technology, without
which  a  data  set  of   over  3.0  million  characters  of
information  would  have  been  overwhelming.   I  thank Dr.
Peter Meier for his enthusiasm and assistance.

      I am very fortunate to have  a family that has been so
unselfish  in  assisting  me  through  my  many  trials  and
tribulations typically  associated  with  such  work.  Their
understanding and confidence provided the necessary strength
to achieve what seemed impossible.

      This  research  was  part  of  a  joint  University of
Michigan-Egyptian  Academy   of   Scientific   Research  and
Technology effort called the Hiver Nile-Lake Nasser project,
funded by the U.S. Environmental Protection Agency Funds for
the analysis of the field data at the University of Michigan
were obtained from the World Bank, contract number 21U26.
                            xvm

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                          CHAPTEH I
                        INTRODUCTION
                 The Disease: Schistosomiasis
    The evolutionary origins  of schistosomiasis most likely
stem from the  great  lakes  region  of  eastern Africa, the
hypothesized cradle  of  man's  ancestors  (Bruijning, 1971).
The host and parasite have over the eons become well adapted
to each other  and,  under  natural  conditions of the past,
severe  widespread  infections  were  unusual.   The nomadic
nature  of  paleolithic  man  left  little  opportunity  for
endemic foci of infections to develop.

    In the papyrus of  Kahun  (ca.  1900  B.C.) is found the
first  recorded   evidence   of   haematuria,   the  classic
presentation  of  .Schistosoma  k§.£.!!L§t;Obiuffl.   The hieroglyph
 A A              — —  —         -»—   _— _— .
,aaa,
 and
depicted  haematuria   and   its   curative  magic  formula,
respectively.  There are tnirty-nine other remedies recorded
on the papyri of Ebers, Berlin, and Hearst (Farooq, 1973).

    Calcified ova of S._  haematobiuj  were found in Egyptian
mummies  of  the  XXth  Dynasty   (1250-1000  B.C.), directly
demonstrating that this parasitic infection did occur in the
Nile Valley during the pharonic era (Ruffer, 1910).  It also
suggests that the highest  attainable  social status of that
period did not exclude  one  from infection.  It is possible
that  schistosomiasis  was   widespread  and  constituted  a
serious problem during this ancient time.  The discovery and
classification   of   the   causative   trematode   (Distoma
h^aematobium) by Theodore Bilharz in  1851 at the Cairo Kasar
El Aini hospital and the demonstration that Bjalinus snails

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were the intermediate host to  the  infection in nan in 1915
at El Margh  village  near  Cairo   (Leiper, 1915), confirmed
Egypt as the MhoaeM of schistosomiasis.  Indeed, Egypt still
remains  the  site  »ost   frequently  studied  by  scholars
interested in this disease, and  the Nile Delta is still one
of  the  world's   most   intense   foci  of  schistosoaiasis
infection.
                              Schistosaiasis
    Schistosomiasis is a  chronic  helminth infection in  man
caused by the  genus  of  tretaatodes ichistosoma.  There  are
three species: S^ haematofaiua, §._, aansoni, and S± ^aponicug.
Two of these  species,  S±  haematobjLum  and  S.. jaansoni  are
found in Egypt and Africa. S.. ja£onicjj§ is restricted to  the
orient.  The life cycle of  all three is very similar.  Each
ovum  (egg) containing  a  ciliated larva (called miracidiuta)
is passed either in human  urine   (Sj, faaeaatgbiua) or in  the
stool  (S. aansoni)  and hatches  en contact with water.   The
freed oiracidiua can  penetrate  the  appropriate snail host
but must do  so  within  a  few  hours  or  die.  The genera
Bulinus, Bioafihalaria,  and  Qncoielania  are the respective
primary snail  hosts  for  JE..  haemaliobiuj!,  S^ ajLEsoiiif  and
J-i 3.§,2.2SicJS! * ^n the  snail  host,  the miracidiura becomes  a
sporocyst which replicates  asexually  to  give  rise to  the
final  larval  form,  the  cercaria.   The  cercariae, after
leaving the snail, are  capable  of penetrating the unbroken
skin of the human host, but will not survive for longer than
twenty-four hours in water.

    Once in the body, the  cercariae reach the portal system
where they mature into male and female adult worms and mate.
The eggs  are  laid  and  released  to  the  outside via  the
bladder or intestine to repeat the life cycle.  The cycle of
infection fron wan to snail and back to man can be completed
in eleven weeks.

    Clinical  features  of  schistosomiasis  include  fever,
hcpatospenoitegaly,   eosinophilia,    lymphadenopathy,    and
malaise.  In S_. haejatobijjj infections, hematuria is common.
Complications  of  the  genito-urinary  tract  can  lead  to
hydronephrosis.  It has been  speculated  that cancer of  the
bladder results from the  calcification of the bladder walls
wbere  eggs  have  been  deposited.   The  duration  of   the
infection in man  has  not  been firmly established.  Viable
ova have been recovered from  persons  who have been free of
exposure for over  twenty  years,   (Warren, 1975) indicating
that  infection, once acquired,  can remain for long periods.
Be~exposure and reinfection lead to increased worm loads  and
therefore to more severe clinical conseguences.  The rate of
spontaneous less of  infection  was  measured  by Farooq  and
Hairston  (1966) in Egyptian  children.   For children aged  5

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and 6 the rate of loss of infection was 0,049 cases per year
for Sj,. haematobi\ij,  S^  J^jQsojai  had  a much higher rate of
less of infection: 0.327 cases  per year.  Higher loss rates
for both species were observed in younger children.

    Exact measures of morbidity  and mortality have not been
Bade.  However,  the  relationship  between  worm burden and
morbidity is roughly  proportional  (Cheever, 1968).  Severe
clinical features are seen in  only a small portion of those
who are infected  (Faroog,et al,, 1966b) .
   The actual role  of  schistosomiasis  as  a public health
problem is not clear.  The contribution to mortality is low.
However, the literature  pertaining  to  the contribution by
schistosoaal infections to morbidity  at the community level
is conflicting {Jordan, 1972).  fieviews by Jordan  (1972)  and
Warren (1975) on  this  aspect are available.  Nevertheless,
it has been  estimated  that  over  200  million persons are
infected worldwide  (Weir,  1969) ,  at  an  annual cost due to
reduced productivity of over $641 Billion (Wright, 1972) .


                      The Setting^ Bc[.y_£t
    Egypt is  made  up  of  several  distinct  sectors.  The
largest  sector  is  made  up  of  the  eastern  and western
deserts, which account for over  90%  of the land aass.  The
area is populated  rather  sparsely  by  nomads,  with a few
stfall  settlements.   Located  in  the  western  desert  are
several more  populated  oases.   El  Kharga  and  El Dakhla
oases, in what is referred  to  as the new valley, are sites
of recent  agricultural  development  and  currently  have a
combined population of about 76,000 persons.  There are also
populated  settlements   along   the  western  Mediterranean
shoreline acd along the  Suez Canal.  Ninety-nine percent of
the Egyptian population is compressed in the Nile Valley and
in the Nile Delta,  3.5%  of  the  country's land mass.  The
population density  in  these  areas  has  been estiaated at
2,400 persons per  sguare  mile  (Haterbury, 1971).  For the
purposes of this  study,  the  Nile  Valley has been divided
into:

      (a)   the delta, or lower Egypt,

      (b)  Upper-Middle Egypt, between the delta and Assyut,
           and

      (c) southern or Upper Egypt located between Assyut and
          the Aswan High  Dam  (AHD) , (See  Figures 1 and 2) .
          Before the AHD  was  constructed,  there existed a
          people, called Nubians,  located between Aswan and
          the Sudanese border.  When  the new lake inundated
          this area, the  Nubians  were resettled, en masse,
                              O

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          in KOEB Oibo,  an  agricultural  plain  about 75 km
          north of Aswan,  and  in  Kheshra  El Girba, in the
          Sudan.

      The population of Egypt  has always been predominantly
"rural," described by Scott (1937) as  persons "whose habits
of life bring them into contact with fields and canals where
infestations with  parasites  may  be  acquired."   In 1937,
11.49 nillion persons were living in a rural setting: 12% of
the total population of  15.92  million.   By 1960, 62% were
rural.  The rural population  has further declined to 56. "\%f
according  to  the  last  census  survey  conducted  in 1976
(CAPMAS, 1976).   Accordingly,  it  is  estimated that 21.45
million persons  are  currently  at  risk  of  acquiring the
infection, assuming  transmission  in  the  urban centers is
nil.  This is  a  relatively  safe  assumption to make since
habitats for the snail vectors, i.e. open canals and drains,
are not found in the  urban  areas  of Egypt.  This does not
mean  that  urban   populations   in   Egypt   are  free  of
schistosomiasis infections.   New  cases  of schistosomiasis
are constantly being brought into the urban areas due to the
steady influx of rural  immigrants who have already acquired
the disease.

    The  distribution  of  the  Egyptian  population  is  as
fellows: 60* of the population  resides in Cairo or north of
Cairo in the Nile Delta  or  Lower Egypt, 23^ live in Upper-
Middle Egypt, and  12*  live  in  Upper Egypt (Quran, 1973).
Males comprise 53X of the total population {CAPMAS, 1976).
                              and Schistgsomiasis
    Bruijniog  (1971) very nicely develops a theme where man,
eaerging  as  a  cultivator  in  the  fertile  basin  of the
Euphrates and Tigris rivers,  tips  the balance of infection
by schistosomes  in  favor  of  the  parasite.  According to
Bruijning,  even  the    earliest  attempts  at  agriculture
included irrigation, and irrigation ditches provided new and
more favorable habitats for  the  proliferation of the snail
vectors.

    The irrigation canals,  ditches,  or  drains, with their
snaller water volume and sluggish movement, form a sheltered
environment aore suitable for  snail growth, compared to the
irregular and  voluminous  discharges  of  the main streams,
Dilution  of  cercarial  output  is  reduced  in  irrigation
ditches, and man and water are brought closer together.

    Although Leiper  (1915) ia Egypt was the first to suggest
the  role   of   irrigation   in  enhancing  schistosomiasis
transmission, it was Khalil (1927, 1935,  1938), also working

-------
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in Egypt,  who  showed  conclusive  evidence that irrigation
scheaes grossly enhanced transmission.   Table 1, taken from
Khalil's study, shows  the  percentage  of persons from four
different villages  infected  with  S_.  haematobium in 1934,
before canals and purcps  were  installed, and in 1937, about
three years after installation.   Over a tenfold increase in
schistosomiasis was observed.   Villages  over one kilometer
away from the new canals  had lower rates than those located
nearby.  The numbers of patients with schistosomiasis at the
local  hospitals  also  increased  dramatically.  Prevalence
remained low in  nearby  areas  which  continued the ancient
"basin11 for» of irrigation.
                           Table 1

       Effects cf Conversion froa Basin Irrigation to
              Perennial Irrigation in Kom Ombo,
         Upper Egypt.  After Khalil and Azim, 1938.

. _L _TT J-
Village




Sebaiia
Kilh
Bimfcan
Mansouria
	 „ i
r
Percent Positive Hith
1934 | 1937*
. , „ , i
.,.,., . j
S. haematobium i S. haeraatobium
•
i
0
7
2
11
,
—
44
50
64
75
>
       *Results obtained by examination of urine and stool
       specimens of 100 persons from all classes in 1934
       and three years later after conversion of the area
       to perennial irrigation.
    Basin irrigation predates all  other forms of irrigation
practices and does  not  create the environoental conditions
suitable for snail  proliferation.   Under basin irrigation,
the low flat lands on  the  banks  of the Nile were  flooded
annually  during  the   late   summer.   The  local  farmers
(fellaheen)would  trap  the  silt-laden  flood  waters using
scall earthen dikes.  After the  silt had settled out on the
land, the water would be  released.  (This was only a slight
modification of what occurred  naturally.)   The fields would
be planted.   This form  of  irrigation produced one crop per

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year, provided it flooded.  Pumps and canals give the farmer
an obvious advantage,  and  an impounded reservoir increases
this advantage.  Damaging  floods  can  be better controlled
and droughts  alleviated.   With  an  increase  in available
water, irrigation systems can  be  expanded to new lands and
cultivation continued throughout the year.

   During the last century  and  early part of this century,
development programs were instituted in Egypt which included
telegraph  networks,  railroads,  harbor  construction,  and
barrages (daas).   Barrages  located  at  Aswan,  Esna,  Saga
Hammadi, Assyut, and  at  the  Mile Delta created reservoirs
for the expansion of  irrigation  schemes.  Previous to this
period, irrigation was primarily basin.

    Nevertheless, by the 1930's the Nile Delta and the areas
south of Cairo to Assyut  (see map. Figure 1) were irrigated.
Only the governorates of Sohag and Qena, along with parts of
Aswan were not irrigated with more modern methods.  Over 85%
of  the  rural   population   were  cultivating  land  under
irrigation schemes that  posed  as sites for schistosomiasis
transmission.

      The  first   aajor   perennial  irrigation  (perennial
irrigation means year-round irrigation and  has been the term
used for irrigation other  than  basin) scheme, built during
the latter part of the  last century was located between the
two branches of the Nile,  the  Eosetta and the Damietta, in
the  Nile  Delta.   It  was  a  huge  scheme  involving  the
construction of  an  elaborate  maze  of  canals and drains.
Soon after its  completion,  the  delta  began producing its
famous long staple  cotton.   Apparently  the digging of the
canals and drains took a brutal toll on the local peasantry.
Thousands reportedly died,  and  where  there presumably had
been only  very  low  levels  of  schistosomiasis infection,
Scott   (1937)  found  in  the  1930»s  that  over  half  the
population in the Nile Delta  was infected, and that in many
areas the prevalence was  over  90%.  This  apparent increase
was guite dramatic and  all  subsequent attempts have failed
to eradicate schistosoaiasis.   Lenoix  (1958) elaborated on
the  relationship   between   irrigation    engineering,  the
iapoundment of  streams,  and  schistosomiasis,  Methods for
controlling snail growth  were suggested.  Farooq  (1966a) has
shown  evidence  obtained   from   field  studies  in  Egypt
suggesting  that  the  type  and  size  of  irrigation water
courses  and the proximity  of  the irrigation watercourse to
the village are important  factors  in transmission.  It was
further  suggested  that  the  t*ro  different  snail vectors,
JLyiiSUs  ai*3  Bigmghalaria,   favored   different  types  of
irrigation  watercourses  indicating  that  transmission  of
these two species of schistosomes occurs separately.

      Impounded reservoirs,  often  indicated for irrigation
expansion, also create new environmental conditions suitable
                              8

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for  snail  vectors  o£  schistosomiasis  to  flourish.  The
shoreline  frequently  provides  conditions  similar  to the
sluggish waters of snail  irrigation canals and drains.  The
acre convoluted the shoreline, the better.

      It should be clear by now that the construction of the
AHD and the  formation  of  the  Lake  Nasser Beservoir, now
approximately 450 kilometers  long, could conceivably spread
the snail vectors of  schistosoaiasis  into the new habitats
created by the  dam  and  the  related irrigation expansion,
and,   with    them,    the   disease.    Environmentalists,
epidemiologists,  and  parasitologists  have  foreseen  this
problem.  Evidence  cited  below  from  other man-made lakes
supports their view.

      Hira  (1969)    and   Rebster    (1975)    reported  that
schistosoiiasis was low in the indigenous populations living
along  the  Zambesi  Hiver  in  central  Africa.   Following
construction of  the  Karbia  Daa  on  the  Zambesi  and the
filling  of  Lake   Karbia,   Hira  (1969)  found  increased
prevalence of schistosomiasis at several lake-side villages.
In school  children,  68. Q%  had  become  infected.  Overall
prevalence as high as 59% was noted.

      In Ghana, McDonald  (1954)   outlined potential medical
problems that could arise from  the formation of Lake 7olta,
the  world's  largest  man-made  lake.   Snail  vectors were
absent in  the  area  to  be  inundated.   Now, Obeng  (1975)
reports that the  snail  vectors  are  common in many places
along  the  shore  and   that  transmission  is  increasing.
McDonald's   concern   was   that   eradication   of   snail
populations,  once   they   became   established,  would  be
difficult, if not impossible,  due  to  the vast area of the
lake.

      The Kainji Lake in  Nigeria  has also created environs
conducive for  schistosomiasis  transmission.  Snail vectors
were present before  dam  construction  (Imevbore, 1975) but
the extent to which the  tribes  living in the river valleys
of this area  were  infected  is not known.   (Unfortunately,
this is  a  typical  situation  in  many tropical developing
areas.)  Dazo  and  Biles  (1970)   studied the resettlements
located  on  the  periphery  of  Lake  Kainji,  Nigeria  and
reported that 31% were  infected.   Follow-up studies a year
later  (Dazo and Biles, 1971)  indicated that transmission was
increasing.  Similar findings have been made by Harinasta et
aL.  (1972) at  Norn  Pong  lake  in Thailand, indicating that
this is a problem of the  tropics in general and not limited
tc Africa.

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                           Controjrersj


      Armed with  the  knowledge  that  daias  and irrigation
schemes in Africa and  in  other tropical regions create new
habitats for snail  vectors,  scientists  and news reporters
alike attacked the AHD as a potential disaster.  The results
of  the  project,   it   was   speculated,  would  cause  an
astronomical increase of the disease in the population.   The
cost of this disastrous  increase  would negate any benefits
of the project,  namely  the  increased  conservation of the
water resources of  the  Nile  and hydroelectric power.   Van
der Schalie (1960,  1963,  1972,  1974) repeatedly expressed
grave  doubts  about  the  AHD  project,   In  one  article,
evidence was  presented  that  schistosomiasis had increased
roughly seven-fold, and  that  this  increase was the direct
result of the  AHD   (Van  der  Schalie, 1974).  These data,
referred to by Van der  Schalie,  were collected by Dazo and
Biles (1971) and are reviewed in the following section.

      Faroog (1967) estimated  that  half  of the population
was already infected, i.e.  14  million  infected of a total
population cf 30 million in 1967.   In areas that were to be
converted or reclaimed,  Farooq  expected  the prevalence to
increase from 5% to  70S,  and  calculated that 2.65 million
new  cases  of   schistosomiasis   would  result  after  the
completion of the AHD  project.  Scott  (1969), whose studies
in  1937  were  the  source  of  Faroog's  (1967)  estimate,
suggested that  there  would  be  at  least  one million new
cases, but added that predictions as high as six million new
cases   had   been   made.     Ayad    (1966)    warned   that
schistosomiasis would increase in the  areas that were to be
converted to perennial irrigation following the construction
of the AHD.  Heyneman  (1971),  in a general article on "mis-
aid11 to the third world,  indicated that impounding the Nile
had directly resulted  in  the  spread of schistosomiasis in
Egypt.  Fogel, et.  al.,  (1970)  estimated  that 60% of the
population of  Egypt  would  become  infected  in  the early
1970's as  the  AHD  complex  was  completed.  Furnia (1975)
stated that schistosomiasis was  mere prevalent now than ten
years ago, "having been exacerbated by an increase of placid
waters from the increased  irrigation canals and Lake Nasser
resulting from  the  high  dam  at  Aswan."   Carter  (1969),
HcJunkin   (1970),  and   Farid   (1975)  reiterated  previous
speculations.  In the Cecil-Loeb textbook of medicine, Lewis
(1971) says.

      Irrigation   schemes   may   have   serious   ecologic
      consequences  for  the   public   health.   In  Egypt,
      schistosomiasis  has  always  been  endemic,  not made
      worse by seasonal flooding of  the Nile.   But in areas
      of perennial flooding, such as   in the delta, there is
      total infestation  of  the  population.    With the new
      Aswan Dam, there will be  large new areas  of perennial

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      flooding, which may greatly increase the spread of the
      disease.

      Sterling (1972),  writing  in  the  popular  press, is
probably the one  nest  responsible  for bringing the "Aswan
High Dam disaster" to  the  attention of the general public.
Numerous  news  media  articles  have  since  appeared  and,
without   fail,   blaae   the   AHD   project   for  Egypt's
schistosomiasis problem.

      However, among all of  the speculation, no aention was
made in any context of the  impact of the AHD project on the
Egyptian Nubian population.  Indeed,  this is a small group,
and this is perhaps  the  reason  that the Nubians have been
overlooked.  Nevertheless, it was  the  Nubians who were the
ones most directly  and  immediately affected, because these
people lived in the Nile  Valley  south of Aswan, and had to
be relocated before the  lake  began  to fill.  The original
hones of the Nubians are now inundated by Lake Nasser.  What
was the  prevalence  of  schistosoniasis  before the Nubians
were aoved?  What is the  prevalence now that they have been
resettled on  a  perennially  irrigated  agricultural plain,
called Koa Ombo,  just north of Aswan?


                     Research Objectives
      The intent of this study is  to assess the role of the
AHD project on  schistosomiasis  transaission in rural Egypt
and in the Nubian population.   In  order to do this, it was
iaperative to collect any  and  all available and frequently
not-so-available  pre-AHD  information  on  the  prevalence,
distribution, and incidence of  schistosomiasis in Egypt.  A
review of this kind has not been prepared since Scott's 1937
work, now 
-------
      4)   evaluate  the  role  of  village  water  supply in
          schistosomiasis prevalence and  the impact of this
          parameter and  other  environmental  parameters on
          transmission,

      5)  desonstrate   the   relationship   between  certain
         aspects of population  dynaaics  and  the spread of
         schistosoaiasis in the rural sites, and

      6)   suggest future needs for  surveillance and control
          strategies for  this disease.

      This study, by comparing current data amassed in Egypt
with historical  data,  is  designed  to  detect  changes in
schistosoaiasis prevalence  and  distribution  that may have
been produced by the presence of the AHD complex.  The rural
populations living  downstream  from  the  AHD were analyzed
separately froa the Nubian population.

      The Review of Literature  in the next chapter analyzes
past survey information in  Egypt,   It  shows what has been
accoaplished in the  past,  it  points  to  current needs in
schistosomiasis surveillance in  Egypt,  and  it serves as a
baseline for establishing changing patterns of transmission.
Thus, it is an integral part of the design the study.
                              12

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                         CHAPTER II
                    BEVIEH OF LITEBATUBE
                        Introduction
     This review is a  survey  of all material, published or
unpublished,  froa   which   data   could   be  obtained  on
prevalence,  distribution,  incidence,   or   any  facet  of
schistosoaiasis  transmission  in  Egypt.   It  includes the
earliest  Material,  dating  from  the  1800's.  Frequently,
historical data of this  type  on  Egypt were unavailable at
the University of Michigan  and  thus  had to fce acquired in
Egypt.  there is  aliost  a  total  lack  of data on pre-dam
health  conditions  and   information  in  other  developing
countries similar to  Egypt  where  huge man-Bade lakes have
been created or are currently being built.  This unfortunate
situation is stressed  because  daas  are  being built at an
accelerated pace, and  without  knowledge  of pre-dan health
conditions  very  little  measure  of  the  impact  of these
projects  on  human  health   can  be  aade   (Baddy,  1966;
McDonald, 1958; Standly and Alpers, 1975).

      Obtaining  historical  data  in  Egypt  poses  its own
problems; thus for the interested worker resource centers in
Egypt have been listed in Appendix  1 as an aid to speed the
preparation  and   documentation   necessary   to  establish
research needs,  design,  and  priorities  that are required
before  work   can   begin.    Several   important  articles
pertaining to this study  were  found  in the Journal of the
JSXEilJfi Pukl-iS  Health  Association.    This  journal has a
very limited circulation in  the  United  States, and is not
indexed.  Often individual  issues  were  without a table of
contents.  It was only  by  perusing  the entire set of more
than 40  volumes,  article  by  article,  that important and
contributing historical  data  were  located.   Indeed, this
review, prepared originally in Egypt, constitutes a research
endeavor in itself.  As pointed out in the Introduction, the
data  reviewed  in  this  section  provide  a  baseline  for
establishing patterns of schistosomiasis transmission before
the AHD was  built.  Therefore,  an analytical assessment of
this  background   data   was   necessary.    Basically,  an
evaluation  of  the  methodologies  used  by  the  different
studies reviewed was made  in order to highlight comparisons
between    different    studies.     Because    of   serious
                             13

-------
aethodological differences,  some  historical  sources had to
be   completely   discarded    as   baseline   sources,   but
nevertheless are included here for completeness.

      It is  remarkable  that  at  this  time  no long-range
policy exists that would  serve  as  an outline of needs for
research activities concerned with surveillance,  prevention,
or control  of  schistosomiasis  in  Egypt.  Furthermore, no
recent  comprehensive  assessment   of   past  data  on  the
occurrence of  this  disease  exists  from  which strategies
could be formulated.  No overview  of the extent or expected
trends  in  schistosomiasis   infections  in  Egypt  has been
prepared.   To  quote  Omran,  et  al^  (1962) ,  "The  use of
epidemiological methods in Egypt has been so fragmentary and
so disorderly applied  that   a  large  amount of  data, which
could  have  been   collected,   was  missing.   Collection,
analysis,  publication, and circulation  of knowledge are far
from being satisfactory."

      It is hoped that this   review will provide a basis for
a more rational development  of future work, and the problems
referred to by Oraran,et  al_.  (1962)  minimized. An inventory
of historical data has  been prepared and respective authors
classified in a master chart.  Table 2 is a list, by author,
area, and  date of publication,  of works in which available
prevalence information  has  been reviewed.
               jork on the Prevalence of Schistosmiasis
      Haeaaturia has always  been  common  in Egypt.  It was
seen in the French armies led by Napoleon after the invasion
of Egypt in the early 1800fs.   In the late 1800«s, a number
of   hospital   patients   in   Cairo   were   surveyed  for
schistosoniasis, and one-third were found infected.  Between
1900 and the  late  1930's,  different  surveys were carried
out, aostly in the  northern  areas of Egypt, with different
findings depending on  techniques  and analyses used.  Table
3, taken from  Azim's  review  (1935) , cites these different
investigators and their  respective findings.  Azim included
his findings of a survey  in  the Nile Delta, shown in Table
4.  These results were  based  on  the number of individuals
positive for either S..  haema^obiua  or SA mansoni in groups
of 200 persons  selected  from  each  village  listed in the
table.  The  results  showed  that  both  forms were common.
Azia  (1935) also  surveyed  areas  south  of the delta where
perennial irrigation had been  installed.  As shown in Table
5, J_. haematobium was found,  and  at high rates, similar to
those in the delta.

      None of the findings cited in Azim's  (1935) review are
comparable,  and  the  lack  of  methodological  information
render them inconclusive.   Nevertheless,  it seems apparent
                             14

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                           Table 2
  Sumaary of Prevalence Surveys for Bilharziasis in Egypt,
                  by Area, Year, and Author
    Area of
     Survey
 Country-wide
 Country-wide

 Mile Delta
 Calyubiya
 Calyubiya
 Calyubiya
 Qalyubiya
 Qalyubiya
 Calyubiya
 Iflaka
 Eeheira
 Eeheira
 Kafr El Sheikh
 Eeheira
 Calyubiya

 Upper-Middle
 Giza
 Giza
 Assyut
 Giza
 Eeni Suef
 fayoua
 Giza
  Year
     1935
     1955

1866-1935
     1936
     1952
     1954
     1956
     1958
     1959
     1963
     1966
     1966
     1972
     1973
     1977

1866-1935
     1949
     1955
     1968
     1970
     1972
     1976
     1977
           Author
           Scott
        EMPH-Hright.

            Azio
      Khalil and Azim
            Heir
          Chandler
          Diaaette
      van der Schalie
          Abdallah
           Sherif
       Faroog, et alv
        Bell, et al._
          Hussein
       Gilles, et a!.
      Alaay and Cline

            Azin
           Khalil
          Zawahry
           Haiaraan
          Abdallah
          Hussein
            EMH
Abdel-Salaa and Abdel-Fattah
  Table Continued
that the prevalence  of  both  foras  of schistosooiasis was
high in the northern delta and that S.faaeaatobiua prevalence
was high in the perennially irrigated areas of the south.

      The  association  between   the  perennial  irrigation
systems and the spread  of schistosomiasis was first clearly
deaonstrated by Khalil and Azia  (1935) in Kon Oabo in Upper
Egypt during this saae period,  as aentioned in the previous
section.  So S_. mansgni infections  were seen by the workers
in this region of Upper Egypt.
                  Sch^stosoBiasis in £
      A brief view of the data for the country as a whole is
                              15

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Area of
Survey


Upper Egypt
Koo Qabo
Sohag
General
Aswan
Aswan
General
Old Hutia
General
General
General
Hew Nubia
General
Lake Nasser
Fisheraen
Fisher «en
Fishernen
Fisheraen
Desert Areas
Dakhla Oasis
Dakhla Oasis
Dakhla Oasis
Dakhla Oasis
Hadi El Natrum
Hersa-flatruh
Table :
Continued

i i

Year



1935
1954
1955
1966
1970
1972
_
1951
1958
1964

1972

1970
1971
1972
1974

1952
1957
1957
1964
1964
1964
i
>
I.

r -....-

Author
. .
r ..-.._. 	 	 	 . .. 	 	

Khalil and Az in
Nooman
EHPH
Tuli
Satti
Dazo and Biles

Dawood
Bifaat and Nagaty
Zawahry
_
Dazo and Biles
..
Satti
Dazo and Biles
Dazo and Biles
Scott and Chu
_
Abdallah
Aziffl
Sifaat, ejt al^
Hifaat and Nagaty
Bifaat, et al.
fiif aat
I
followed by a nore  detailed review of information available
for each of the  following  sectors:  the Nile Delta, Upper-
Middle Egypt, Nubia,  Lake  Nasser,  and  the Desert Sectors
(which have been grouped together).
               Country Slide Prevalence Surveys
      Only two  surveys have been carried out in Egypt which
saapled the entire  country,  excluding  Nubia, Lake Nasser,
and the Desert  Areas  and  are  comparable.   The first was
completed in 1937  by  3.  Allen  Scott,  and the second was
completed in 1955 by the  Egyptian Ministry of Public Health
                              16

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                           Table 5

             Prevalence of Bilharziasis in Areas
             South of Cairo. After Azim (1935).
                             Percent Positive With
       Village	
                        S. haematobiua       S. aansoni
Oussim
Kafr Asiar
Bolida
Abahaway
Senouris
Koso Aba Badi
Ashaant
Beni Bekhit
Dashut
El Fant
Kefour
Sheikh Fadl
69
73
71
70
69
71
60
70
80
61
72
60
0
0
0
3
a
12
0
5
17
17
12
8
(EMPH, later to become  the  Egyptian Ministry of Health and
to be referred to as EHH)   and was reviewd by aright (1973).
In 1965 a third  study  was  completed  by the EMPH, but the
results are  of  limited  value  due  to  the differences in
methodology  between  this  study   and  the  previous  two,
Following a general review (See below) of these two surveys,
details  of  these  studies  are  elaborated  on  under  the
appropriate  geographic  subheading   to  illustrate  points
pertinent to the particular locale.

      In 1937, Scott  (1937)   reviewed  the previous studies
and coapleted the  first  country-wide  survey.  Some 40,000
individuals were examined on  a random house-to-house basis,
Scott (1937) supplemented these  data with results collected
from  over   2,000,000   examinations   made  at  government
treatment centers.  In summary,  Scott (1937)  found that 60%
of the population was infected  with both forms and 83* with

-------
either one or both foras in the north and eastern sectors of
the  Nile  Delta.  In  the  south  central  delta,  60% were
infected with £_.  haeaatobium  and  656  with S^ I§.nsoni.  In
Middle-Upper Egypt, in areas under perennial irrigation, 60S
of the population was  infected  with S_. haegatobiua, and in
those areas in Opper  Egypt  under basin irrigation, only 5%
of the population was infected with S_. haeaatobiua.  Figures
3  through  5   are   naps   showing   the  distribution  of
schistosomiasis  according  to  Scott.   S^  lanscmi  had  a
distinct and liaited geographical distribution in the delta,
and S^ haeiatobiu»! was °£  1°"  prevalence in the area south
of Assyut but generally high elsewhere. By 1937, in the area
north of  Assyut  (Upper-Middle  Egypt) perennial irrigation
schemes had  been  constructed  and  were  by  far  the aost
predoninant aethod of cultivation, as in  the delta.  In the
area south of  Assyut  {Upper  Egypt) ,  the  older method of
basin irrigation was still  the  aost common type practiced.
The association  of  irrigation  practice  and prevalence of
schistosoaiasis found by Scott  (1937) reinforced Khalil and
ftzia's (1935) observations.   later,  Nooaan,  et al. (1974)
also found an increase in prevalence of S^ haejatabiuai, froa
5.6X to 71,63$, in an isolated  area of Upper Egypt which had
been converted from basin to perennial irrigation.

      It is clear  that  by  the late 1930*s schistosomiasis
was quite widespread in  Egypt.   Indeed, in the Nile Valley
north  of Assyut  the  prevalence  of schistosomiasis in the
population had no doubt  reached  a  peak by this tine.  The
conditions sere ideal for  transmission, as control programs
did not  yet  exist  (Faroog,  1973),   The  only aspect not
clearly understood was, "Shy was  J_. JS.a.nsoni only located in
the  northern  and  eastern   delta,  and  not  parallel  in
distribution to S._ haefflatobiua?"

      Scott  (1937)  suamarized  his  findings  nationwide to
show that 17$  of  the  population,  which  at that time was
about 15.23 million people, were infected with either one or
both foras of schistosoaiasis.   He  considered this to be a
very conservative estiaate.  He further pointed out that the
population living  in  the  area  between  Assyut and Aswan,
estiaated  at  just  over   2  million,  would  come    under
increasing risk of being infected as plans had already  begun
to convert the area to perennial irrigation.

      By 1955, the  EflEH  coapleted  a  follow-up to Scott's
work (1937) using the  sane saapling and laboratory aethods.
The villages selected were  also  the  saae sites studied by
Scott (1937) twenty years before.  Soae 124,253 persons were
examined,  nore  than  three  times  the  saaple  population
examined by Scott   (1937).   Bright   (1973) has reviewed the
1955 findings and ccapared that  data with the 1937 data, as
shown in Table 6,  It is clear that:

      (a)  a   fall   in    the    overall   prevalence   of
                             20


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23

-------
           SA  kaema tobiii J»  from   48%   to  38%,  and  for
           £. aansoni, from 32% to 9%, occurred between 1935
           and "1955,

      (b)  the decrease  in  prevalence  of  Sj  ,§§JL§onjL was
           consistent for  all  infected northern provinces,
           and

      (c)  while the  overall  prevalence  of JET. ha.ej.atobj.um
           had decreased, there  had  been significant, even
           alarming increases south of Assyut in Suhag.

      The results of  the  1955  survey  do  not include the
number of those persons  with  mixed infections and thus the
total prevalence of  schistosomiasis,  or all those infected
with either one  or  both  species  of Schistosoma cannot be
calculated froo this data. It is unfortunate that the design
of the survey did  not  include  this aspect. Those infected
with both species of  Schistospaa  should not be ignored for
it  is  this  group  which  bears  the  greatest  burden  of
morbidity and   mortality  (Scott,  1937).   Halawani  (1957)
attributed the decline in  prevalence  from  1937 to 1955 to
governaeat  anti-bilharziasis  campaigns  which,  he pointed
out, began in earnest in 1942,
              Schistosoaiasis in the Nile Delta
      In  1936,   Khalil   and   Azim    (1936)  showed  both
S_s haematobium and S^ fflansoni prevalence to be high  (55% and
5S%f respectively) in a site 25  KB  NE of Cairo in the Nile
Delta.  A  H%  sample  of  the  population  was selected and
divided into two groups,  depending  on whether the selected
individual was working near the village canal in the east or
not near it in the  west.   Those working near the canal had
somewhat higher  prevalence  of  S_.  jansoni  than those not
working  near  the  canal.    No   difference  was  seen  in
prevalence   of    Jj,    feS^matobiuj    between   locations.
Considerable differences were  noted  between sexes for both
species, the sales having the higher rates.

      In 1952, Heir, et  al_.  (1952) ,  under  the auspices of
the  EMPH  and  the  fiockefeller  Foundation,  completed  an
intensive four-year study  on  the  health and sanitation of
the village  of  Sinbis,  Qalyubiya  Province,  in the south
central delta.  In  the  course  of  the  survey, the entire
population, some 4,232 persons, was examined.  An evaluation
of  the  housing  standards,   water  supply,  fly  control,
latrines,  and  refuse  disposal  was  made   of  the  entire
area. Data  collected  included  the  presence  of  lice and
fleas, diseases of the eyes, nutritional status, vaccination
status,  serological   examination   for  syphilis,  enteric
fevers, tuberculosis, malaria, and  an examination of stools

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26

-------
and urine for parasites.  High  prevalence for both forms of
schistosomiasis was  found,  38.4%  for  S^  haeaatgbium and
12.5% for Sj.  aansoni.   Furthermore,  on reexamination of a
subsaople, Weir  found  an  even  higher  proportion  of the
population, 88%f to  be  positive  for S.. haematobium.  This
alaraing demonstration of  false  negatives  resulted from a
change  in  methodology  by   Heir   in  the  screening  for
S.S. k§§15l5iijlJ •  Boutinely,  SA  ha§SlJ5^i!JS is detected by
an examination of the urine for characteristic ova.  This is
done siaply by  collecting  the  urine  in  a conical flask,
allowing it to sit for  a period of about half-an-hour, then
examining the contents of  the  sediment  by low power light
microscope.  The ova  have  a  higher  specific gravity than
urine, and, if present,  will  be concentrated in the bottom
of the flask.  Because of the  ease with which this test can
be employed, it has been widely used.

      Two methods  were  used  to  produce  the  increase in
positives.   In  one   of   these,   the   urine  was  first
concentrated by centrifugation and the sediment suspended in
water, followed by projection of the specimen on a screen to
search  for  hatched  miracidia.    In  the  second,  rectal
scrapings  froa  each  individual   were  examined  for  the
presence of ova. The  rectal  scraping method of examination
was found to be far superior in revealing infections.  It is
unfortunate that this method  does  not  lend itself to mass
screening procedure.

      The   implications   of    Heir,   et   aJU.'s   (1952)
demonstration of large numbers of false negatives are that

      1)   all the  previous  surveys  had underestimated the
          prevalence of S^ haematobium, and

      2)   when  the   simple   sedisentation   technigue  is
          employed an  estimate  of  probable false negative
          error should be included  in the results,  A whole
          new light is  thrown  on Scott's (1937)  estimates.
          Presumably the prevalence  should  be increased in
          areas from 6056  to  QQ%.   Certainly  no less than
          half of the population  was infected in 1937,  when
          Scott's (1937) results  were  published:   over 7.6
          million in  a  total  population  of  15.2 million
          persons.

      Weir,  et  al_.'s  (1952)    study  also  suggests  that
S_, nansoni was invading a  new territory.  i careful look at
the maps in  Figure  5  shows  that  in  1937 S^ nansoni was
almost non-existent ia the  south  central area of the delta
in which  the  village  of  Sindbis  is  located.   Heir, et
aJU (1952) however,  found  a  prevalence of 12.5%.  Scott's
highest prevalence found for the  sane area was only 7%, but
it was usually much  lower  and  frequently zero (1937).  No
data were collected for  Sindbis  itself  by Scott (1937)  in
                             27

-------
1937, and, therefore ,  it  is  possible that the area could
have been an  isolated  focus,  or,  even  more remotely, an
extension of  infection  from  the  not  too  distant south-
eastern sector where  S._  mans on i  was  more  common. A more
likely  explanation  is   that   the  higher  prevalence  of
-Li iansoni in  Sindbis  was  the  result   of differences in
technique by the surveyors.   The rectal scrapings technique
certainly would have reduced  the number of false negatives,
as compared to  the  nore  routine  methods of examining the
stool directly for J_. aansoni  ova  as used by Scott  (1937).
Apparently Seir, ejt alj.   (1952)  employed the rectal scraping
technique only for J^ jjaji.liLtob.ium detection (although it can
be used for SA jansoni  as  well)  and, like Scott, relied on
the  traditional  method  to   screen  for  S_.  jansoni.    A
prevalence rate of 12Jt,  therefore,  may  be  too high to be
explained just by differences in techniques.

      Chandler (1951) carried  out  a  follow-up on Heir, et
a_i^'s (1952) study two years  after its completion and found
that the aass cheaotherapy  progran  implemented by Weir had
reduced the prevalence of schistoscmiasis to isolated cases,
It is doubtful,  however  that  the  prevalence continued to
remain  low.   Treatment  does   not   reduce  the  risk  of
reinfection.   Indeed,  this  has  been  one  of  the  major
frustrations of treatment  control  programs,  i.e.,  after  a
course of treatment has been finished, it has been difficult
to keep the cured  patient  free from the readily accessible
snail-infested canals and drains.

      Table 6 includes the results  from the 1955 EMPH study
for the delta sector  and  compares  them alongside those of
Scott's   (1937)  study.    A   decrease  in  S__,  haematgbium
prevalence from 57* to 45X,  a proportional drop of 12%, can
be seen for the delta.  Decrease in prevalence is seen to be
greater in some governorates  than  in others.  For example,
the decline was much  greater  in Qalyubia than in Gharbiya.
What  is  remarkable  is   the   very  uniform  decrease  in
prevalence for 5.. aansoni for all governorates in the delta,
except in Minufiya, which was low to begin with.

      Dimaette (1956), in  a   study  to detect neoplasms of
the bladder, found 31.7$  infected  with S.. haeraatobiun in  a
sample  taken  from  the  Qalyubiya  Province  census, which
agrees  remarkably  well   with   the   1955  E«PH  results.
Qalyubiya was also the  site  for two other projects  carried
out between 1953 and 1959.   In  a review of these projects,
Abdallah  (1973) reports that  Helay  from the EflH found that
before treatment 44.551 of  the  population was infected with
S_- feaematobiua and  2.6X  with  S..  jaansoni.  Treatment with
tartar  emetic  reduced   the  figures  to  30. H%  and  1.151,
respectively, over  a  period  of  five  years.   The second
project   was  a  joint  American/EMH  effort  by  Berry  and
Halawani  (1973) and  was  designed  to assess mollusciciding
only as   a  method  of  reducing  schistosomiasis infection.
                             28

-------
Only  children  between  6   and   19   years  of  age  were
examined. S_. iL§€j|atobijm  was  reduced  from 40.2% to 24,2*,
an^ Jj. 5§5§SUl *as reduced from 5% to zero during the eight-
year period of the project.

      It. should be pointed  out  that prevalence of shedding
of ova in the 5-  tc  9-year-olds  is  never the same as the
prevalence in  the  general  population,  which is generally
lower.  This is true  for  both forms of schistosomiasis and
is irrespective  of  the  seasonal  pattern  of transmission
(Farooq, et al_.,  1966).   The age-specific distribution for
schistosoaiasis in endemic areas  has  been shown to be very
characteristic.   Figure  6   shows  the  sex-adjusted  age-
specific prevalence curves  for  four different surveys. The
sane pattern is  shown  in  each  one.  The prevalence rises
quickly in younger children, falls sharply in the teens, and
then falls Bore  gradually  thereafter  and generally levels
off at a much lower rate in middle age.  The younger groups,
therefore, provide  a  more  sensitive  measure  for control
assessment,  as  they  are  the  age  group  most frequently
positive.  Generally, prevalence  differs  according to sex,
with males leading, especially  those occupied as farmers or
boatmen.  Therefore,  crude  unadjusted  data  aay differ by
area depending solely  on  the  structure of the population.
Per example, the prevalence may be artificially depressed in
an area  with  more  woaen,  all  other  things being equal.
Generally, this is net  a  problem  in Egypt, because of the
similarity of composition in the rural populations.

      There is an  exception.   The  population in Aswan and
Nutia  has  a  low  Hale:female  ratio  resulting  from male
emigration to the  northern  cities  for employment, leaving
behind the adult  females  and  children.   This  has been a
continuous migratory pattern since  the turn of the century.
Currently, the  trend  has  changed  somewhat  to moving the
family nucleus as well.  Labor demands from neighboring Arab
countries contribute to  the  depressed ratio. Therefore, in
this area crude rates might underestimate true prevalence.

      Wright    (1973)   reviewed   the   results   of  urine
examinations on 60,197 persons, which  are shown in Table 7.
The  survey  involved  23   different  villages  in  various
locations in Egypt to  show the age-sex specific prevalence.
This was a companion  field  study  to the 1955 EHPH survey.
Prevalence in males was slightly  higher than in females and
reached a laximum at 10 tc  14 years of age.  Both males and
females showed the typical increase in prevalence during the
early years, reaching a peak  in  the teens and tapering off
after the early  twenties—the  classic age-sex distribution
of schistosomiasis in Egypt.

      Sherif  (1968) found  somewhat  higher prevalence rates
ic Iflaka.  Iflaka  is  in  the  Beheira  governorate in the
northwestern delta, where S_.  lansoni is also found.  Sherif
                             29

-------
          100

          90

          •0

          70

          60


         ! M
         J
         I.
          40


          30

          20

           10


           0
SINOBIS, 1949
"~ —~-^  . . EL-SIUF, 1956
         M.O.P.H., 1955
                   10      20      30      40      50      60
                                 AGE IN YEARS
Figure  6.   The  prevalence  of schistosomiasis  in four surveys.
After Qnran  (1973).
                                   30

-------
(1968)  detected  63.2%  with  S^  haematobjLuffl,  60.6%  with
S_j oansoni, and 82.2 with either one or both; and termed the
area "hyperendeaic."   These  prevalence  figures  suggest a
sharp increase since  the  1955  EMPH  studies for this area
(see Table  6).   Possibly  If laka  was  an  atypically high
prevalence  site,   again   reflecting   the   highly  focal
distribution of  schistosomiasis.   Another  explanation for
such  an  increase  may  be  the  result  of  differences in
methodology.  It is difficult  to  determine the exact cause
of the differences based on the information available.

      In 1966, also in the  Beheira governorate, west of the
Iflaka  area,  one  of  the  aost  comprehensive  studies of
schistosoniasis in Egypt was  completed.  This was the joint
HHO-UNICEF-ESH "Egypt-49" pilot control project, directed by
M. Farooq  (Farooq and Nielsen, 1966).  Approximately 5% of a
total population of  250,000  persons were examined.  Socio-
economic, environmental, and  cultural  factors,  as well as
domestic water habits, were  included  in  the study, as was
the examination of  urine  and  stools  for schistosome ova.
The  sample  population  was  selected  from  four different
sectors  or  divisions:    rural,  reclamation,  urban,  and
control. The control sector served  as a comparison site for
the others in which measures against schistosomiasis were to
be tested. Prevalence for one or  both forms was high ia the
control  sector  (59.5%),  in  those  who  were  occupied as
farmers (50.6%), boatmen and  fishermen (60.4%), in males in
the 10-14 age group (84.4%), in those who could neither read
ncr write  (32.2%),  in those  who  swam (61.9%), in those who
washed clothes and utensils in  canals (50.2%), in those who
lived in mud or mud  brick  houses (46.4%), and in those who
did not have piped  water  (53%).  The relationships between
schistosomiasis  prevalence,  regardless  of  type,  and the
different independent  variables  follow  very  closely what
might be expected,  i.e., those  who have most water contact,
who are less educated,  who  have  inferior housing, and who
use the canals as a  drinking  and washing water source have
higher prevalence  rates  than  their  counterparts.  It was
also expected that those who had latrines in their homes and
used them would have lower rates (32.5%),  than those who did
not have latrines  in  their  houses  (47.9%).  In addition,
these results show  that  by  far  the lowest prevalence was
found in those persons who have latrines in their houses but
did  not  use   them   (10.8%) .   This  somewhat  surprising
observation was  found  consistently  throughout the project
area in each division. A further analysis based on subject's
age and type of house  showed  that the non-users were often
very young  children  whose  rates  for schistosomiasis were
generally low anyway.   Age, however,  was not the determining
factor for nud brick or  inferior houses for which the rates
were again the lowest for those who had latrines and did not
use them.   In  this  analysis,  the difference in prevalence
between having a  latrine  and  using  it  and  not having a
latrine was very  small,  and  for  the  poorer housing, not
                             O I

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significant.  No truly satisfactory answer was provided.

      It would have been worthwhile to exaaine the method in
which the use or  non-use  of  a latrine was determined.  No
elaboration of this method was  available in this article. A
definition Bust  precede  the  formulation  of the question,
since observation seems unlikely,  and it is this definition
that must be  analyzed,  as  well  as  the data. Results are
directly affected by the methods  with which they are taken,
and without knowing the methodology employed, interpretation
is difficult.

      Another interesting relationship  shown  by Farooq, et
ajU (1966)  was  that  between  the  age,  sex, and swimming
habits, and  the  prevalence  of schistosomiasis.  Infection
with both species was twice as great among frequent swimmers
as among non-swimmers,  fluch  higher rates for swimaers were
consistently found for either species or for schistosomiasis
in all four divisions of the project area.  Of the males who
swam, 57.3% were between the  ages  of  5 and 19, and 53% of
the female swimaers «ere  between  5  and 14.  Male swiaaers
outnumbered female swimmers four to one.  The overall higher
rates in young  swimming  males  strongly  suggest that this
group's activities play an  extremely  important role in the
continued transmission of schistosomiasis  in Egypt.

      Figure 7  shows  the  similarity  of  the age-specific
prevalence for the different forms of schistosomiasis in the
four different  project  divisions,  again demonstrating the
characteristic and universal  pattern  of  high rates in the
young and lower rates in the adults.  "Bilharziasis" in this
figure refers to those  who  are  infected  with one or both
species of  schistosomes  and,   as  pointed  out  before, is
synonymous *ith the  term  schistoso/aiasis.    In the overall
project  area  29.7%  had   S±  haema_tobium  and  28.5%  had
5-s 13S§2£i»  Prevalence of  mixed infections (those infected
with both) is always less than  for either of the two or for
"fcilharziasis".  In the overall  project area 17.2% had both
S-s kSSSStofciuB and _£_. jansjgni,  and 40.9% either one or both
or bilharziasis.  These results  are  summarized in Table 8.
Significant differences were  noted  in  the Egypt-49 study,
not only between  divisions,  but  also between villages, as
well as between different parts of the village.

       Even more recently, in the north central delta and in
Middle Egypt, a project on  health manpower sponsored by WHO
and  the  High   Institute   of  Public  Health  (Alexandria
University) ccmpleted  a  survey  in  1972  which included a
measure of prevalence on several human parasitic infections.
(Hussein,  1972).   The   sample   population  was  selected
systematically froa a frame or  list of all families in each
of five villages in an area near the town of Kafr El Sheikh.
Some  4,177  persons  were  selected,  of  which  13.4% were
positive for  S.  haematobium  ova  in  the  urine and 15.4%

-------
60
ts
c

*'* '"'% D
rroiect Areo
/ ^
     0   5   10   15  20  25   30  35  40   45  50  55  60
    0  10  20  30  40   50  60  0   10  20  30   40  50   60
                       Age (years )
" Bilharziasis "
S. mansoni


S. haematobium
Mixed infection
Figure 7.  Age prevalence  distribution of schistosomiasis in  the
Egypt-49 project area and  in its  four divisions.   After Farooq,
et al. (1966).
                                    34

-------
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-------
positive for S_, maasoni ova  ia  the feces  (about 8% did not
give a specimen).  Table 9 shows the age-sex distribution of
S_. l»l£J!§i2i>i3J  and  S,.  jansoni  infection  in the selected
population.   Infection  with   either  species  followed  a
typical distribution with slightly  higher prevalence in the
sales.

      These findings are  the  lowest  in  prevalence so far
seen for this area of  the  delta.  If those individuals who
did  not  give  a  specimen  had  been  positive,  then  the
prevalence  would  have  increased   to   20%  and  23%  for
iLs fe3S5Ji2^1jS5 an<* S.. jaosoni, respectively.  This is still,
however, a decrease for S_.  haematgbium when compared to the
1955 findings, which were 52%  for this same area  (note that
Kafr El  Sheikh  was  part  of  the  Gharbiya governorate in
1955) , and  only  slightly  raised  for  S..  lansoni.  These
findings suggest  that  the  prevalence  of  S_.  aansoni has
changed only  slightly,  and  S._  h§ejatobium  has decreased
since 1955.

     The aost recent data  collected  in Egypt on prevalence
and distribution  of  schistosomiasis  was  gathered  in the
Qalyubia governorate in 1976  by  Alamy and dine  (1977).  A
systeiatic sample  of  every  fourth  household was selected
froa eight villages.  Twenty-seven percent of the population
was found to be infected  with S_. haematobium and 40.5% with
jLa 3§S§21ii»  Egg  counts   of  the respective specimens were
made, which is frequently used  as a measure of intensity of
infection, e.g., the  Bore  eggs  shed  the  more severe the
disease.  Relatively low  intensity  of  infection was found
for both species:  a  geometric  Bean  output of 9 eggs/1Occ
urine for Sj  baematobiua  and  12.8  eggs/gram of feces for
S_. najisoni.

      In 1955, the prevalence of  J_.  fflansoniL was 3% and for
                 ¥as  31X  in  Qalyubiya,   The  decrease in
               prevalence of  k%  is  only  a modest one and
could be explained  by  a  number  of factors, including the
typically  focal   nature   of   the   distribution  of  the
disease.   The   high   prevalence   of   S.   Sajisoni,  an^
correspondingly low egg count,  are, however, very important
observations.  Looking  back  at  Scott's   (1937)  work  (see
Figure U) , just to  the  north  and  east  of where the Nile
branches into  the  Sosetta  and  Daaietta  is  the  area of
Qalyubiya, where S^ aansoni was also very low in 1935.  This
is the saae area where  the  eight village  sites selected by
ilamy and Cline  (1977) are  located and where the prevalence
of JA jansoni has now jumped  froa spotty isolated foci to a
level indicating a major change, not only in prevalence, but
also in distribution.

      Alaay and Cline  (1977)  have scrutinized their work in
an effort to explain the  changes observed  in the prevalence
of £.  manscni.   Soae  possibilities  are:  a)   From snail
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-------
studies done by Alaasy and  dine   (1977) in the early period
of the study, it was shown  that a much  higher proportion  of
JLt ansoni, and for
either  one  or   both   infections   (schistosomiasis).    It
declines continually for all cases from  1935.


            Schistosoaiasis in Upper-Middle Egypt
      Freguently the environs south  of Cairo, including  the
Giza plateau, are referred to  as  Upper Egypt.   For purposes
of presentation here, the area south of Cairo  to Assyut  will
comprise Upper-Hiddle Egypt  and   will include the following
governorates: Giza,  Fayua,  Beni  Suef,   Minya,  and  Assyut.
Upper-Middle Egypt, as pointed  out earlier, was, except  for
a few isolated areas,  perennially  irrigated  by the  1930's.
The region south of Assyut  to Aswan, where  basin irrigation
was  still  predoainant  in  the   1930*s,  constitutes Upper
Egypt.  The area south of Upper Egypt is called  Nubia.

      Less historical  data  on  scbistosoaiasis exists  for
Upper Egypt than  for  the  delta.   One   of the most coamon
features of Nile Delta  surveys  was  that they  were  located
                              38

-------
                          fable 10
        Percent Prevalence of Schistosomiasis in the
          Northwestern Nile Delta by Selected Years
      Xear
  1935(Scott)

   1955(EMEH)

  1966(Farooq)
Perc

S. haematobiun

53

46

29,7
:ent
• i 	 '" -
i
1 s«
-L~—
I
\
I
I
1
I
Prevalence
, ^^i
mansoni

54

31

28.5
a
Either
One or Both

83

—

40.9
                                             .j	
       Prevalence of human schistosomiasis for the
       governorate of Beheira ia 1935, 1955, and 1966.
       Prevalence data for infection with either one or
       both species of schistosomes for 1955 is not
       available.  The data cited for 1966 have been
       corrected for the proportion found positive in three
       examinations on consecutive days.
within easy reach of  either Cairo or Alexandria.  Distances
considered short in  the  developed  world render many sites
inaccessible in the developing  world because of poor and/or
crowded  road   conditions   and   inadequate  communication
systems.  Moreover,  a  number  of  important survey support
facilities can  only  be  found  in  the larger metropolitan
areas. Atteipting  surveys  south  of  Cairo in Upper-Middle
Egypt has been and continues to be a formidable logistic and
administrative challenge that increases with distance.

      In 1935, Azim  surveyed  a  number  of sites ia Upper-
Hiddle Egypt, as  shown  previously  in  Table 5.  From each
location, 200  persons  were  selected,  presumably using an
appropriate  method,   and   examined   for  infection  with
S_. k§§S5*2biSJ an<* Sj.  aaasoni.  The findings were uniformly
high for  S.,  haeoatobium  infection.   Unfortunately, it is
difficult to determine the  location of these surveys simply
from the name of the  village.  Up-to-date maps of Egypt are
either restricted or non-existent.  Not only are many of the
villages Baied in this survey not present on available maps,
but repetition of village names is common.

      Scott  (1937) and the  EMPH«s  1955  study are the only
investigations attempting  to  survey  the  whole  of Upper-
Hiddle Egypt,  The coverage of both surveys, although spread
throughout, was spotty.  Scott  (1937)  supplements this with
                              O -?

-------
data collected from governmental treatment centers which, as
it turns out, agree rather  well with his findings, although
different   sampling    methods    were    employed,    Only
J-j ^I§5Ji2^iil5 infection  was  found.   As  has been stated,
Sj JSSnsoni «as not found  in  the southern delta or south of
Cairo.  The prevalence of S_.  k^SMiobium ranged from 41% to
90?, with an  average  of  60*.   Figures  4  and 6 show the
distribution of  S^.  hjematobium  obtained  from  the random
house-to-house survey and from the treatment centers for the
area between Cairo  and  Assyut,   The notable uniformity is
the  result,  of  widespread   use  of  perennial  irrigation
throughout the  area,  which  had  been established sometime
before Scott's study (1937).

      Table 6 shows  the  results  of  the  1955 EMPH survey
compared  alongside  Scott's  (1937)   results.   The overall
prevalence declined from  52%  in  1935  to  32% in 1955.   A
decline was also seen in each governorate.  In Giza, both in
1935 and 1955,  sporadic  cases  of  S_.  mansoni were found.
Local  health   officials   claimed   that   infection  with
JL» mansoni in Giza or  in  any governorate south of Giza can
be assumed to have  been  acguired   from the northern delta.
This assumption  is  becoming  increasingly  risky  to make,
especially in light  of  the  recent evidence from Qalyubia,
where the  distribution  of  S,jBansoni  is clearly changing.
Other more localized surveys  have   been  carried out in the
Fayum, Giza, and in Assyut,

      In 1955, Zawahry selected  a random sample of children
from 0-12 years old, based on  a 1954 social census frame in
Shubramant, Giza {Zawahry, 1962),    A sample of 762 children
were selected, of which 691  gave specimens, 71 others moved
or died, and 43 results were inadvertently lost.   (It should
be noted  that  such  detailed  accounting  of  the selected
population is freguently overlooked  when data are presented,
and correspondingly the  analytic  value  of  the results is
limited.)  Helminthic and  protozoan parasites were screened
from the urine  and  stool  specimens.   Of the males, 25.9%
were infected with Sj. haema^tojjium.   No J^. mansoni infections
were found.

      In  addition,  Zawahry    (1962)  made  an  interesting
observation.  He found  that  the  tilharzial children had  a
greater likelihood  of  having  a  multiparasitic infection.
That is, the prevalence  of  infection with another parasite
was higher in those  children  with  S_. haematobium infection
than in children who did not have bilharziasis.  It would be
interesting if this relationship is  true also for S± mansoni
infection, and if other specific parasites were involved.

      Abdallah  (1973), in  1970,  surveyed  a nearby area of
Giza,   Shanbari,    and    found    31.2%   infected   with
Ji-s haematobium.  The  survey  was  carried out in connection
with  a  control  project  measuring  the  effectiveness  of
                             40

-------
hycanthone as  a  cheaotherapeutic.   No  fflollusciciding  was
dene.  A reduction to 2Q% over a year's tine was achieved,

      The Fayoun is an  area  of  400,000 feddans and can  be
seen on the aap in Figure  2  as  a bleeb of the Nile to  the
west, south of Cairo.  The  water  for this area is supplied
through a single source  canal (Bahr Youssef) which branches
into almost 10,000 km of irrigation canals.  In 1949, Khalil
(1919) surveyed  2-6  year-old  children  in  the Fayoum,  of
which he  fcund  65,1X  infected  with  S± k§SS§^2^iiiI-   Tne
number  of  those  examined  for  each  age,  the  number  of
positives, and the  percentage  positive  are shown in Table
11.  A characteristic increase can  be seen with the advance
in age up tc 6  years.   In  1968,  4555 of the population  of
atout 880,000 persons were infected with _§._ haematobiua.   No
Sj, mansoni infection has ever been detected in those who  had
never travelled outside the Fayoum,
                          Table 11

          Age-Specific Prevalence of J_. haeaatobiua
                    in the Fayoum, 1949.
                    After Khalil  (1949) .
     Age
   (Years)
No.  Examined
Nc. Positive
Percent
     2

     3

     4

     5

     6
     20

     51

     68

     96

     112
5
26
38
65
92
25
51
56
77.
82.



6
1
   Totals
     347
    226
  65.1
      Scott (1937)  had found a somewhat higher prevalence in
the Fayoun: between 67-8435.  Since 1968, the Fayoum has been
the site of  a  massive,  and apparently successful, control
project, carried out  in  cooperation  with  the EMH and the
German  Federal  Republic.   Prevalence  has  been  steadily
reduced to 8.116, its present  rate (Mobarkic, 1975).  It was
convenient that an  effective  application  could be Bade at
the Bahr Youssef Canal, just before it enters the Fayoum and

-------
branches,  thus  avoiding  a  piecemeal  application  to the
40,000 km of canals.  Niridazole was used for mass treatment
of the population with emphasis on the school children.  The
health units and primary and secondary schools were employed
for administration of  treatment.   This effort continues as
au ongoing control program as of this writing.

       It will  be  interesting  to  follow  the dynamics of
*Ls  k3§13tobium  eradication,   When  prevalence  is plotted
against year, the curve seen  in  Figure 8 iias a shape which
suggests one of  diminishing  returns.   In the Fayoum, 8.1X
corresponds  currently  to   about   89,000   persons  in  a
population of 1.1 million, which  is a sizeable reservoir of
infection.

      In the Assyut  area,  four  villages  were surveyed in
1968 by Haanan,  et  al.  (1975).   This  study was the most
recent   of   those   concerned   with   demonstrating   the
relationship between irrigation  systems and schistosomiasis
transmission.  Systematic samples  were  taken  at the study
sites,  and  urine   specimens   were   examined  by  simple
sedimentation.  A prevalence of 34,5% was found in the three
villages located in  areas  that were perennially irrigated.
In  a  fourth  village,  where  basin  irrigation  was still
enployed and, according to  Hamman,  et  al^  (1975) the only
village of its kind  remaining  in the Assyut governorate at
the time of the study,  the  prevalence was only 3%*   {It is
not  clear  what  Hamman,  et  alj.   (1975)  means  by "basin
irrigation".  The flooding of  the  Nile  River in Egypt had
ceased altogether  by  1964,  when  the  coffer  dam  at the
dcwnstreaa diversion  canal  was  dynamited  and Lake Nasser
began to fill,  After 1964,  the annual flood, necessary for
basin irrigation, was trapped by the rising water of the new
lake.)  When this village  is  included with the other three
villages, the combined prevalence is  25%.  In the 1955 EMPH
study, 16% of the sampled  population of Assyut was positive
f°r J.. haejatotnUiji which is  36%  less than Hamman, et al^'s
(1975) findings  of  25%.   However,  the  prevalence in the
three villages with perennial irrigation schemes, i.e. 34.5%
is probably acre  representative  of  Assyut  as a whole and
indicates an even greater increase.

      In  1955, three  of  the  villages  sampled by the EMPH
study   were   still   using   basin   irrigation   and  had
correspondingly low prevalence,  which,  when added together
with  the  findings   from   the  villages  using  perennial
irrigation, resulted  in  depressing  the overall prevalence
given  for  the  area.   Apparently,  the  selection  of the
village  sites  by  the   two  studies  reflected  different
research objectives.  A more  meaningful comparison might be
one where prevalence  only  in  the villages using perennial
irrigation is used.  The  prevalence  data for 1955 for only
those villages in  Assyut  using  perennial irrigation comes
fro» a separate parallel study  by the EMPH in which methods
                             42

-------
 O
 2!
 UJ
 LU
 o:
 CL
 LJ
 O
 cc
 UJ
 Q.
40

35

30

25

20

 15

 10


  5
       0      68  69  70 71   72  73  74 75

                              YEARS
Figure 8.  This graph was plotted after data obtained from the
EMH (1975) for the Fayoum governorate schistosomiasis control
project.  The first year of the control program was 1968.
                            43

-------
of irrigation and  the  prevalence  of schistosomiasis were,
like Hamman, et  al_.*s  (1975)   study,  also being evaluated
(Wright, 19737-  The results of that study showed 68% out of
19,043 persons examined  were  infected with S_. haematobium,
or twice that found in 1968,                              ~

      Increased use of  perennial irrigation systems results
in increases in  schistosomiasis  prevalence  in Assyut.  In
the Assyut governorate  between  1955  and  1968 the limited
amount of  land  under  basin  irrigation  was  converted to
perennial  irrigation,   It  is  possible  that  an  overall
increase in prevalence followed,  but that the prevalence at
any given site  under  perennial  irrigation  over this time
period aay have been  dropping.   If  this  had not been the
case,  Haraman,  et  al^'s  results  for  the  villages using
perennial irrigation in 1968 would have been higher.

      As part  of  the  1970  MHO-High  Institute  of Public
Health study mentioned previously in the section on the Nile
Delta, a  sample  population  of  3229  persons was selected
systematically from five  villages  near Beni Suef  (Hussein,
1S72).  The study  site  is  approximately  150  km south of
Cairo in an area southeast of  the Fayoum and has been under
perennial irrigation from  before  1935.   The prevalence of
SA baejatobiuj for  all  five  villages was 24.1%.  Thirteen
persons were found to have  S.. mansoni infections.  Figure 9
shows the age-sex prevalence distribution.

      Like the  parallel  study  in  Kafr  El  Sheikh, these
results indicate that  the  prevalence  of S^ haematobium is
also declining in  Beni  Suef,   especially  when compared to
Scott's  (1937) findings in the  1930's of 82*  (see Table 6).
The 32% prevalence found  by  the  EMPH  1955 study might be
taken as  an  intermediate  point  in  a  long-term downward
trend.

      Sex related differences in prevalence have, of course,
been  recognized  for   a   long   time,  with  males  being
significantly higher.  The reason  most often cited for this
is that the Bales are at higher risk due to the occupational
necessity  of  having   increased   water   contact  in  the
agricultural fields.  This  is  not an entirely satisfactory
explanation for the  difference.   Harked differences can fce
seen in the very early years, and in the adult age  group the
difference in prevalence between  the  sexes often is not as
much  (Farooq et al_., 1966;  Hussein, 1972).  In the Egypt-49
project  (Farooq,et ajU 1966) and in the Kafr El Sheikh study
(Hussein, 1S72) the  differences  in  prevalence between the
two sexes were less than six percentage points.  However, in
Beni Suef the prevalence in  males  was more than twice that
of the females,  32,3*  and  15.5H, respectively.  A similar
observation was made  by  Hamman,  et  al.. (1975) in Assyut.
Differences in  prevalence  in  male  and  female  by region
cannot be analyzed from  data  collected  by Scott  (1937) or
                             44

-------
   60
    50 -
LU
O
    20 H
    10 J
                              	  MALES
                              	 TOTALS
A
;  \
                            	  FEMALES
               i
               10
                       \
                      40
20     30

    AGE (YEARS)
60
Figure  9.  The age-sex specific prevalence of S^. haematobium in
selected sites of the Beni Suef governorate in 1972.  After
Hussein (1972).
                             45

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the 1955 EMPH study  (bright,  1973).  Both studies combined
their  findings  from   different   regions  of  Egypt  when
presenting sex-specific data.   This  is unfortunate, for it
would be interesting  to  see  if a sex-related differential
was developing over time.

      There is an obvious need here for sex-specific data to
be collected and presented in a Banner that would facilitate
comparison  by  region,   There   are  no  answers  or  even
implications  of  what  changes  in  sex-specific prevalence
aight mean {perhaps an  indication  of  the impact of health
education), but this is no reason to ignore them, especially
when this is siaply a  aatter of research design rather than
additional field work,

      In brief,  the  surveys  carried  out  in  the area of
Upper-Middle Igypt are in general agreement with each other,
•Li 3§fi§2£i was not present or,  if so, could be explained by
showing that the  infected  persons  had  spent  time in the
delta or  had  originated  from  there.   S_, haema^tobium was
found uniformly throughout the  area at a prevalence similar
to that of the delta and reflected the widespread conversion
of land from basin  irrigation  to perennial irrigation,  In
fact, S± ba§S§tobruj  infection  had  been  abundant from at
least the middle of the  1930's.   In the future, the Fayoum
must be considered  separately  as  an  area of Upper-Middle
Egypt where schistosoaiasis is rapidly coming under control.


               Schistosomiasis in Upper Egypt
      The area of the Nile  between Assyut and the old Aswan
Daa is termed (Jpper Egypt,   When Scott (1937) surveyed this
area in 1937, basin  irrigation was practiced throughout the
district  except  in  the   Kom  Ornbo  plain.   Large  sugar
plantations were developed in   Kom  Ombo during the 1930*s,
reguiring the conversion  of  land  to perennial irrigation.
The Kom Ombo plain is similar to the Fayoum aneurysm, except
that it is smaller in area  and  bulges to the east, not the
west.  The Kom Ombo plain  is  not as "pinched off" from the
Nile as the  Fayoua  and  is  watered  by numerous different
canals rather than a single  canal as in the Fayoum,  Figure
10 is a LANDSAT photograph of  Kom Ombo, Aswan, the AHD, and
a northern portion of Lake Nasser,

      Khalil and Azim's  (1935)  research into the causal role
of perennial irrigation  schemes,  pumps,  and canals in the
"introduction of infection with  S_. haema^obi^m" was carried
out in Koa Omfco in the early 1930 *s.  Khalil and Azim  (1935)
surveyed villages before  and  after conversion to perennial
irrigation and found that  prevalence reached levels similar
to that of the delta  in  as little as three years following
conversion.  These results are shown in Table 1.
                             46

-------
              *&.
Figure 10.  This is a photographic reproduction made by a LANDSAT
satellite of Upper-Middle and Upper Egypt.  Included in the lower
portion is Lake Nasser.  Just north of Lake Nasser is Aswan and the
Kom Qmbo plain.
                                47

-------
      Scott  (1937) found  in  1937,  however, that the areas
north and south of Kom Ombo  had a very low prevalence of S_.
^J^natobiuj.  Again, no S_,  J5S.Iiso.si  tfas seen.  The previous
Figures t and 6  show  this distribution, which included the
results  taken  fron   governmental  data.   Generally,  the
prevalence of J_, haejatobium was 5% or less in Upper Egypt,

      Data from the EHPH  1955  survey  as  shown in Table 6
reveal soae of the most  dramatic increases in prevalence so
far seen.  In two of  the three governorates of this region,
Sohag  and  Aswan,  the  prevalence  increased considerably,
while in Qena it  regained  unchanged.  The increase from 35E
to 41% in Sohag  reflects  the conversion of the governorate
to perennial irrigation previous  to  the 1955 study.  Large
proportions of the Aswan  governorate were also converted to
perennial irrigation, which  already  included  the Kom Ombo
agricultural   plain.    Correspondingly,   the   prevalence
increased frota 13% to 23%.  The increase probably would have
been greater had the  remaining  portions of the governorate
still using  fcasin  irrigation  (the  northern  part  of the
governorate and south of the Kom Qffibo plain) been converted.

      Between 1955  and  the  1960*s,  the Qena govercorate,
which was predominantly  basin  irrigated, and the remaining
areas of the Aswan  governorate under basin irrigation, were
converted to  perennial  irrigation.   What  has happened in
these areas since  thea  is  probably what everyone expects,
but  little  current   information   exists  except  for  an
unpublished iHO report by  Dazo  and Biles  (1972).  Although
unpublished, the report has  been widely circulated and even
quoted as evidence of the impact  of the AHD on the increase
of schistosomiasis prevalence  (van der Schalie, 1972).

      In this  influential  study,  sites  were  selected in
Assyut,  Idfu  (50  ka  north   of  Kom  Ombo),  the  Nubian
resettlement sites of Kom Oabo,  and  in the Aswan area.  No
sites were  selected  from  urban  areas  or  from  the Qena
governorate.  In  the  area  of  Assyut,  S± haemajiobJLuiB was
fcund in 30* of those  examined from two villages.  In Idfu,
an  overall  prevalence  of  75%  from  three  villages  was
obtained.  Jrom  the  three  villages  surveyed  in Aswan, a
prevalence of 32.H%  was  found,  and  for  Nubia a combined
prevalence  of  19%   was   observed.    These  results  are
summarized in Table  12.

      Certainly these findings show an increase  compared to
the level of prevalence seen in the 1930's.  An increase was
expected  since  there  had   been   ample  tiae  since  the
conversion to perennial  schemes  fcr prevalence to increase
when Dazo and Biles  (1972)  carried out their survey.  There
are, however, certain aspects of this survey that render the
results epideaiologically  unsound.   First,  it  is obvious
from a brief  examination  of  the  data  that the method of
selection did not provide a representative sample population
                              48

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49

-------
fcr age or  for  sex.  The  younger  age groups were greatly
over-represented in the sample, and, as pointed out earlier,
in Upper  Egypt,  especially  in  Aswan,  adult  females far
outnumber the adult sales  in the general population.  There
was not a single village  surveyed  by Dazo and Biles (1972)
where  more  wonen  were  selected  than  men.   That  could
possibly have been corrected  by appropriately weighting the
selected population for  age  and sex.  This, unfortunately,
was not done.  The sajor difficulty, however, is one of non-
response and self-selection.   If  100 persons are selected,
using an appropriate  »ethod,  and  results are obtained for
only fifty, the non-response rate  is 50$, or the number not
giving results/total selected X 100.  To give only a typical
exaaple, in the village of  Mankabael near Assyut, there are
13,000 inhabitants.  All those  between  2  and 25 years old
were requested to give  a  urine  specimen.   A total of 123
responded and  gave  specimens.   Eased  on  their method of
selection this is over  a  99% non-response rate.  It cannot
be presoeed  that  the  non-respondents  are  typical of and
sinilar to the respondents.

      It  would   be   very   worthwhile   to   have  recent
quantitative data  for  Upper  Egypt.   However, the results
froa Dazo and Biles  (1972) and of Tuli  (1966), who completed
a limited survey in Aswan, only indicate that SA haematobiuf
is present. The exact  proportion of the population infected
cannot be deternined with any certainty froa these reports.

      In brief,  very  little  recent  or  accurate  data is
available for Upper Egypt.  The prevalence of £_. haematobiua
was  low  in  the  area   prior  to  the  use  of  perennial
irrigation, but the entire area  has since been converted to
perennial irrigation.  It  is  expected  that S± haematgbj.ua
infections would greatly  increase  following the conversion
tc perennial irrigation systems,  and  data provided by Oa^o
and Biles  (1972) and  also  by  Tuli  (1966) indicate that it
has.  The exact  figure  of  increase  and  when it occurred
reaains, however, unknown.


                                  IS jjubJL_
      Egyptian Nubia was  formerly  the  area along the Nile
Valley between the old  Aswan  Dam  and the Sudanese border,
now inundated by Lake Nasser.  The population from this area
is quite  distinct  from  the  general  Egyptian population,
having  different  styles  of  dress  and  language.   Three
separate tribes, the  Kenuz,  the  Arabs,  and  the flahas or
Fadiga, comprised about 50,000  persons.  All nere resettled
in New Nubia in 1961  when  the rising waters of Lake Nasser
began to flood  their  original  hose  sites.  New Nubia has
been constructed along the eastern periphery of the Kom Orabo
agricultural  plain.   The  villages  retain  their original
                             50

-------
names and geographical distribution,  with  the Kenuz in the
north, the Arabs in the  middle,  and the Mahas or Fadiga in
the south.   Often  neighbors  were  settled with neighbors.
But a population living along  400  km  of river bank is now
compressed into an area approximately 50 km long bordered on
one side by  a  canal,   Figure  11  shows this resettlement
pattern.

      Dawood    (1951)    recognized    that   bilharziasis,
transmitted by snail vectors,  was  present in Nubia but did
not  provide  data  on  distribution  or  prevalence  of the
infection.  Rifaat and  Nagaty  (1958)   surveyed the Nubians
for   a    number    of    health    parameters,   including
schistosomiasis.  Seven villages were surveyed, and some 553
urines were examined.  Table  13 shows these results.  Table
13 also shows to which tribe the village belongs and whether
or not perennial  irrigation  schemes  were  present.  It is
interesting to note  that  perennial irrigation schemes were
being installed at this early  date in Nubia.  Also shown in
Table 13 arc the number examined at each village, the number
positive for Schistosoja ova  in  the urine, and the percent
positive.  An overall prevalence of 40% was obtained.  Table
1*1 shows the age-specific  prevalence  rate with the younger
members having a typically higher prevalence.  Table 14 also
shows the number of each  age  and sex who were examined. It
is guite evident that  the  females, especially in the older
age groups,  were  under-represented.   fiifaat  and Nagaty's
(1958) survey suffers from the  same defects that were found
in the study by  Dazo  and  Biles   (1972).   Not only is the
population  incorrectly  represented,   but  the  method  of
selection is not discussed  ,  making  it impossible to know
the probability of being  selected.   It  is known that 1369
persons were, by some unknown  method,  selected and that 553
gave  urine  specimens,  which  is  a  40%  non-response for
specimens alone,  Accordingly, these results cannot be taken
as accurate estimations of the prevalence of schistosomiasis
in the Nubian population at that time.

      It is very fortunate  that  a  survey just previous to
the resettlement of the Nubians  was  carried out in 1964 by
Zawahry  (1964) in  which  the  shortcomings  of the previous
surveys, and those of  many  of  the  surveys of Egypt, were
avoided.  A multi-stage  stratified  random  sample based on
the 1960 population  census  representing  each of the three
tribes was the frame for sample selection.  Every individual
in the Nubian  population  had  a  chance of being selected.
This chance was calculated  as  a  probability, which is the
basis of  any  sound  statistical  analysis  of survey data.
From these prevalence  figures  estimates  can  be made with
given degrees of confidence.

      An  overall  estimate  of  15.2%  of  the  Nubians had
S_» hjL§matobiua, less  than  half  that  found  by Rifaat and
Nagaty   (1958).   Because  of  differences  in  methodology,
                              3 I

-------
Figure 11.  This is a map of the Kom Qnbo area showing the resettle-
ment pattern of the Nubian tribes.
                                 52

-------
                          fable 13

       The Percent Prevalence of S_. haem atobiujB, 1958.
              After Hifaat and Nagaty7 1.1970) *
    Village, Type of    No. Persons  No. Positive
  Irrigation, and Tribe  Examined   S_, haematobiam Percent
      El Dakkah             132           47         36
      Perennial
      Kanooze Tribe

      Kurta                  83           12         14
      Basin
      Kanooze Tribe

      El Malki              104           67         63
      Basin
      Arab Tribe

      Einefca                 87           11         12
      Both
      Fadiga

      Ballana                82           56         68
      Perennial
      Fadiga

      Arainna                32           12         37
      Basin
      Kanoo2e
      Total                 520          205         39
        *Caution should be taken when interpreting these
        findings.  There is no evidence to show that the
        population selected was representative.


especially sampling  protocols,  it  is  quite impossible to
compare the  two  surveys.   However,  the  work  of Zawahry
C1964) lends itself  easily  to  future studies or follow-up
studies for purposes  of comparison.  Naturally, comparative
studies require  that  laboratory  and  other data gathering
methodology be consistent.  This is only possible if details
of the methodology employed are described as was the case in
the report by Zawahry (1964),

      All tec  frequently,  reliable  baseline  data  do not
exist for  populations  in  Africa  and  in other developing
                             53

-------
                          lable 14

   Age-Specific Prevalence of S^ haemat.oj>ium,  Nufcia,  1958,
         After M. A.  Bifaat and I. F.  Nagaty,~(1970) .

Age
(years)
0-4
5-9
10-14
15-19
20-29
30 +
ALL AGES

X Positive for
S_. haematobium
, 	
56.0
30.0 Total Saraple=1,3
43.0 Males=1,083
14.0 Females=3Q4
18.0
40.0
areas  where   large   man-made   lakes   have  been  built.
Demonstrations of changes  in  health  patterns arising from
lake-Making are difficult, if  not impossible, when data are
lacking  prior  to   dan  construction.   Typically,  impact
statements  on  the  effects   on   health  of  these  water
aanageaent schemes  rely  only  on  data collected following
construction  of  dans.   Zawahry's  (1964)   work  makes  it
possible to assess accurately the Nubian population now that
they have teen resettled.  Trends  can be estimated, and the
impact  of   the   environmental   changes   resulting  from
displacement can be made.

      Details of Zawahry's  results  have been reproduced in
Tables 15, 16, and 17.  Table  15  shows  the age and sex of
persons who gave  urine  or  stool  specimens by village and
tribe.   The  total  sample   of  925  individuals,  closely
reflecting the demographic  composition  of  the 1960 Nubian
population  were  selected.   Table  16  shows  the  age-sex
specific prevalence for the sample.  Typically higher levels
of prevalence are seen in the younger groups. The prevalence
by village, hamlet, and sex  can  be  seen in Table 17.  The
dramatic difference  in  prevalence  between  Kurta  and the
other  two  villages   reflects  differences  in  irrigation
practices.  Snail surveys  carried  out  by  this study were
unable to find vector snails  along the Nile banks, although
a total of some 44 ka were surveyed and 1320 dips were made.
Snails were found in 751 of the 600 dips made in canals where
perennial irrigation projects had been established.
                             54

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55

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      As mentioned, Dazo and  Biles  (1972) surveyed a sample
of Nubian resettlement  villages  in  1972  in  the Kom Ombo
agricultural plain.  It  their  estimate  of 19% prevalence,
which is not a great deal  different from the 15.2% found by
Zawahry, is  true,  then  little  change  ia schistosomiasis
prevalence has resulted from relocation.  These two surveys,
however,  lack  comparable  features  in  their methodology.
Thus, any conclusions drawn  must  be  taken with the utmost
skepticisa.   Certainly   no   unequivocal   epidemiological
statements can fce made.

      It can be concluded  that recent accurate estimates of
§•. Jn§Ii "I» the only species  present, in Old Nubia have
been nadc, and the  provisions  of the methodology have been
let providing grounds on  which  reliable assessments can be
made in the future.
               Schistosomiasis in Lake Nasser
      In 1964, the coffer data  at  the head of the diversion
canal, just scuth  of  the  new  AHD,  was dynamited.  Hater
began to fill in  behind  the  then yet uncompleted AHD.   By
1970, the AHD was  completed,  and  by 1975 Lake Nasser had,
predictions  outstanding,  filled.   All  of  Old  Nubia was
flooded, which included agricultural  lands  and a number  of
pharaonic sites.

      HHO sent four aissions  to  lake  Nasser in the period
between 1970 and  1974.   Satti   (1970) estimated that there
were 3307 fishermen working along the shores of the lake and
examined   about   14X,   or   463   persons,   for  urinary
schistosomiasis. Twenty-nine percent had infections, and 45%
of a  smaller  group  of  fishermen  examined  at  the Aswan
Hospital had  infections.   Dazo  and  Biles  (1971) surveyed
fishermen along the entire length of the lake and found that
51 % of 111 were infected.  The  only permanent population  on
the shore of Lake Nasser  is  at the Abu Simbel temple.  The
134 persons  there  cannot  be  considered  local indigenous
inhabitants, but are rather Government employees coming from
a variety of locations   from  all over Egypt.  Nine percent
had S_. haematobiua  infections.   The remaining shoreline  of
the lake was "a vista  of  barren  rock and arid sand"  (Dazo
and Biles, 1971).  In  1972,  23  out  of 32 fishermen  (72*)
were demonstrated to  have  Sj..  hiieraatobium infections  (Dazo
and  Biles,  1972).    In   1974,   Scott" and  Chu   (1974),
consultants for HHO, reviewed  these findings  and concluded
that it  was  impossible  to  tell  if  infection  was being
acquired from the lake or  from endemic areas of Upper Egypt
during periods when fishermen  were visiting their families.
Each investigation included a malacological survey.  Between
1970 and 1974, snails of  the species .Bulinus trjnc_at,us, the
vector host for  S±  haema^obium,  were found throughout the
                            "56

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lake in the south as well  as  the north and on both eastern
and western shores.  A  large  number of foci were observed.
So infected snails were found  except near the High Dam area
of the lake.

      In brief,  Lake  Nasser  is  populated  fcy 3,000-5,000
transient fishermen and  there  are no permanent settlements
located along the shore of  the  lake, except at  Abu Simbel
where  there  is  a  small  group  of  government  personnel
stationed for maintenance and care  of the temples (Dazo and
Biles, 1971).  There  are  vector  snails present throughout
the lake.  There is an indication that a large number of the
fishermen are infected with S.. haematobiuni.  Transmission in
the lake say fce limited to the area near the AHD.
    Schistosoniasis in the Desert and Reclamation Sectors
      The remaining settleaents  in  Egypt are located along
the western Mediterranean  shore  and  at  desert oases.  In
1952,  the   population   of   the   Dakhla   Oasis   had  a
schistosoaiasis   prevalence   of   65%    (Abdallah,  1973).
Repeated sollusciciding had reduced  this prevalence to Q.1%
by 1957 (Nagaty and  Rifaat,  1957).   Rifaat et aJU, (1963)
confirmed these  again  in  1963.   Rifaat,  et  a^..  (1964)
surveyed Wadi El Natrun,  also  a  desert  site, in 1964 and
found only those that had  recently come from the Nile Delta
had schistosoaiasis infections.  Also in 1964, Bifaat (1964)
looked at the western coast  at Herso-Matruh and again found
the area free of schistoscniasis.

      Those areas of Egypt  not  watered  by the Nile, i.e.,
the western coastal region  and  desert area, are apparently
free of schistosomal  infections  either  because of control
programs or  because  of  the  lack  of perennial irrigation
schemes.

      Hew reclaimed lands comprise  important new areas into
which the  schistoscme  species  have  a  high likelihood of
being  introduced  because   of  the  associated  irrigation
expansion.  The area between Cairo  and Assyut is an example
of land  reclamation  that  took  place  over  40 years ago.
Reclamation in this  discussion,  however,  will be reserved
for those areas in  which  there  was no previous indigenous
population  and,  thus,   must   be   settled  with  persons
originating from elsewhere.  An  example  of such an area is
cited in the  previously  mentioned  Egypt-49 project in the
Beheira Province,  Moreover,  because  of the new additional
water resource, some  1X106  feddans  have been proposed for
reclamation.  It is interesting to note that while new lands
have beea reclaimed in the  last  15 years, there has been a
net loss of cultivated land  in Egypt due primarily to urban
sprawl,  military   construction,   and   road  construction
                              o y

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(gaterbury, 1974) .  Also, after  the outbreak of hostilities
in 1967, reclamation activities were delayed,


            Schistosoaiasis in Egypt;  A Summary
      In Egypt, schistosomiasis, also known as bilharziasis,
is  caused  by  infection  with  either  S..  haeaatobium  or
§A  S§IL§P.Si f  or  both.    Snails  of  the  species  fijalijnis
Il-yficj-tys an<3  Bioaphalaria  alexandr^ina  are the respective
vector hosts.   Schistosoaiasis  in  Egypt  has been present
since pharoaic  times.   In  the  latter  part  of  the last
century and in  the  early  part  of  this century, the Nile
Delta  was  converted  from  basin  irrigation  to perennial
irrigation, which brought with  it widespread infection with
both  species  of   schistosoaes   and  rendered  the  delta
"hyperendemic".   Recent  studies  in  the  delta  show that
schistosomiasis is still  quite  prevalent,  although not as
high as it had been earlier.  Numerous control projects have
been   carried   out,   and   it   should   be   noted  that
mcllusciciding, cheaotherapy,  environmental and educational
programs have been, and  continue  to be, ongoing activities
at the some  2140  rural  health  units  and centers, in the
secondary schools, and at  the 162 endemic disease treatment
centers.  The  relationship between perennial irrigation and
schistosomiasis    transmission    has    been    repeatedly
demonstrated.  In addition,  S^  JJfisofii infection was found
to have a  limited  geographical  distribution restricted to
the delta.  Sporadic cases  have  been  seen  in Giza and in
Beni Suef.

      Before 1910, prevalence of j>_. haematobium was found to
be high (603? cr more) in  the  area south of Cairo and north
of  Assyut   where   perennial   irrigation   has  been  the
predoainant method of cultivation.  This includes the Fayoum
area.  Recently, control  programs have considerably reduced
the prevalence of  S..  haematobiuj  in  this area.  The data
from  1955  strongly  suggest   that   an  overall  drop  in
prevalence was occurring when compared to the 1937 studies.

      From Assyut south  to  Aswan,  only  S^ haematobium is
found, and before  1940  S_.  iiaematcbium prevalence was very
low, except in the  Ron  Ornbo  plain  (Scott, 1937).  Surveys
carried out  between  Aswan  and  Assyut  in  1972  (Dazo and
Biles, 1972) inconclusively suggest  that  there has been an
increase in S^ haeaatobium prevalence since the area has now
been completely  converted  to  perennial irrigation.  Basin
irrigation was no longer found after  1965 in Egypt  (Dazo and
Biles,  1972).   Excellent  historical  data  exists  on the
prevalence  of  schistosomiasis  in  the  Nubian populations
before resettlement in the Kom Ombo plain  but no conclusive
studies have been completed  to assess changes following the
Nubian resettlement.   Clearly,  these  two  areas are prime
                             60

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sites  for  assessing   changing  patterns  of  schistosoraal
infections.  This does not  mean  that studies should not be
carried out on the fishermen  populations in Lake Nasser, or
at reclamation sites.   Indeed,  surveys are currently being
organized to  follow  schistosooiasis  transmission  in Lake
Nasser by the EHH  as  a  companion  study to the 8HO inter-
regional project  (IB  9658RAF/71/217)   on schistosomiasis in
Lake Volta, Ghana.
                    Expansion and the Aswan High Oam
      Since irrigation  schemes  are  a  critical  factor in
transaission and  spread  of  schistosomiasis  in  Egypt and
because irrigation schemes were  to  be  expanded as the AMD
complex was completed,  it  is  important that all available
information concerning the development and implementation of
irrigation projects in Egypt be  included  as a part of this
review.

      To reiterate, both the reclamation of ne* lands (lands
uncultiTatable previous to the  AHD because of limited water
resources) and the  conversion  of  basin  irrigated land to
perennially irrigated  land  were  cited  as  projects which
would result  in  the  increase  of  schistosoiiasis  in the
population.  Th€ areas of interest for reclamation have been
in the eastern desert regions between the Nile Delta and the
Suez Canal and west of  the Nile Delta, south of Alexandria,
where  reclamation  has  been  very  active  in  the  recent
past.  Since  the  1930*s  virtually  all  land  under basin
irrigation has been located  in  Upper  Egypt,  and it is in
this  area  that   schemes   for   conversion  to  perennial
irrigation have been focused.

      The  term  "perennial   irrigation"  has  been  rather
loosely applied, usually  indicating  simply the improvement
over basin irrigation by installing pumps to raise water for
cultivation rather than wait nine months for the next flood.
In effect, basin  irrigation  in  Upper Egypt was frequently
being  * supplemented"  during   the   months  without  flood
waters.  A  good   example   of   this  type  of  "perennial
irrigation" was described by Khalil and Azim (1938)  in their
original work on the  impact  of  irrigation schemes and the
transmission of  schistosomiasis  in  Upper  Egypt.   Another
example was in old   Nubia  where  pumps and canals had been
installed at selected sites as pointed out earlier (Zawahry,
196-iJ), and where schistosomiasis had increased.  In villages
where standard basin irrigation was continued, without puraps
and canals, prevalence was low.

       The type of pump  used  for these earlier "perennial"
schemes was characteristically  a large gasoline-driven pump
housed  on  a  floating  platform  (see  Figure  12).  These
                             61

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"floating pump houses", which are still commonly seen locked
along the  river  banks  of  Upper  Egypt,  were designed to
provide water to canals regardless of wide variations in the
water level or  discharge  of  the  Nile  typical of the era
before construction of the  AHD.    Many of these pumps still
function,  but  government-funded  irrigation  expansion has
installed acre  modern  electrically  driven concrete-housed
pooping complexes capable of lifting much greater volumes of
water,  thus   increasing   the   potential  for  year-round
cultivation,  Irrigation engineers  typically refer to these
schemes  as   perennial   or   "permanent"  irrigation,  and
irrigation practices previously  used were vaguely described
as basin irrigation.   In  a  sense  this is correct because
land was flooded in  Upper  Egypt  before the coffer dam was
cleared in 1964 and  the  lake began to fill.  Nevertheless,
the floating pumps and their  related canals and drains were
also present. This has resulted  in a degree of confusion as
to what has  been  irrigated  and  how  in Upper Egypt.  The
number of floating pumps, when  they were installed, and the
amount of land serviced is  not known, as productive sources
of information on the  development  of irrigation schemes of
any  kind  are  scarce.   The  data  obtained  from Egyptian
governmental sources (EG,  1977)   and translated from Arabic
(see Tables  18 and 19)   provide  a limited amount of insight
on the number of feddans converted to "permanent" irrigation
in Upper Egypt.  According  to  the data reproduced in Table
18, Aswan was completely converted to "permanent" irrigation
daring the period  between  1933   and  the  present, and, by
1974, there  were 92 thousand  feddans yet to be irrigated by
"permanent"  methods in all  of Upper-Middle and Upper Egypt.
Table 19 is  a  more  detailed  break-down,  by year, of when
irrigation  conversion  by  the  governmental  agencies  was
carried out.  For example the 282 thousand feddans available
for conversion in Qena  governorate  were irrigated by 1969.
There was no change  in  the  number of feddans converted in
the Sohag gcvernorate from 1965 to 1974, indicating that the
irrigation projects were  completed  by  1965, except for 34
thousand feddans still  to  be  converted.   A  total of 881
thousand feddans of Upper-Middle   Egypt and Upper Egypt were
converted to "permanent"  irrigation  in  the 15 year period
between  1959  and  1974,   according  to  these  government
figures.

      Note in  Table  17  that  the  region  proposed  to be
irrigated in 1959 in  Sohag  comprised 295 thousand feddans,
virtually the entire area  of this governorate. According to
the  inforaatioc  in  Table  17,   the  government  engineers
apparently   considered  Sohag   as   an   area  under  basin
irrigation   in  1959.  However,  the  results  of  the  1955
schistosomiasis survey  (EMPH,  1955)   showed sharp increases
in schistosomiasis prevalence indicating  that at least some
man-made  irrigation  schemes  were  already  present.  This
increase occurred  before  the  iaplementation  of the large
"permanent"   government    funded    irrigation   projects.
                             62

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                               64

-------
                          Table 19
        Conversion to "Permanent" Irrigation by Year
                  in Selected Governorates
                     After Shindy (1977)
 Sear
                            Governorate
       Cunulative Nunber of Peddans Converted (in Thousands)
         Qena
Schag
Assyut
Minya
Beni Suef
Before
1965
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
282
38
50
201
282
282
282
282
282
282
282
295
261
261
261
261
261
261
261
261
261
261
266
239
239
239
239
256
266
266
266
266
266
86
0
0
0
0
11
44
61
64
69
71
44
0
0
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0
0
0
0
1
1
1
Otviously, pumps, mcst likely  the  kind shown in Figure 12,
and canals had been installed  in many areas of Sohag during
the late 1940's and early  1950*s,  but there are no data to
confirm this.  The question is,  "Did Qena, after 1955,  when
schistosomiasis  prevalence  was  still  low   (EMPH,  1955),
expand  irrigation  systems,   using   the  'floating  pump'
system?"  It is probable that,  like the other areas of Opper
E9ypt» Qena's first irrigation  expansion occurred before the
AHD complex was  begun.  The  "floating pump" structures can
still be seen  docked  along  the   Nile  banks  of the  Qena
governorate, indicating that  at  some  point  in time these
pumps were used for  irrigation.  Therefore, the possibility
should be  considered  that  schistosomiasis  prevalence had
increased or was  increasing  in  the  governorates of Upper
Egypt/ as  a  result  of  these  earlier irrigation methods,
before  the   iiplenentation   of   the   larger  government
irrigation schemes, and before  the AHD was begun.
                             65

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      Haterbury (1974)  has  pooled  information  on land and
water use in Egypt in an excellent review article.   Table 20
from Haterbury's (1971)   article  shows  the cropped area by
season and year,  Note the drop in number of feddans cropped
ic the autuam between  1952  and  1966.   It was during this
season that the Nile flooded,  After 1964, cultivation could
be increased during the productive summer months.  Figure 13
graphically shows the  interesting  relationship between the
growth of the population and agricultural expansion.

      According to Waterbury (1974), more land was reclaimed
before the AHD than after  it.   By 1973, 902,000 feddans had
been reclaiaed, of which  about  half were being cultivated.
Bany of the areas selected  for reclamation were of marginal
quality reguiriag great  expenditure  before cultivation was
possible.  Indeed,  the   agricultural   area  seems  to  be
decreasing rather  than  increasing.   Although  902,000 new
feddans had been  added,  there  was  a  net loss of 200,000
feddans by  1973  due  to  urban  expansion,  road building,
factories and military installations.

      Aside from the fact that  land reclamation seems to be
rather liaited at this time, there is doubt that reclamation
as  such  is  a   mechanism   for  causing  an  increase  of
schistosomiasis  in  Egypt,    To   illustrate  this  point,
envisage an area, devoid of farms and settlements.   «ith the
increase in  available  water,   the  area  is  irrigated and
developed  into  state  farms.   Families,  most  likely non-
landowners, are  brought  in  and  settled.  These resettled
faailies and their  members  are  now  at  risk of acquiring
schistosomiasis, but were they not already at risk?  Are not
many of then  already  infected,  having long since acquired
the infection at village homes in the delta or in the south?
It is  doubtful  that  many  of  the  families  that move to
reclaiaed lands originate  from  urban  settings. Thus, land
reclamation  imposes  a  risJc  of  changing  the  geographic
distribution of the  disease,  but  is  unlikely to cause an
increase  in  the  prevalence   of  schistosoaiasis  in  the
population.   Changes in the distribution of schistosoraiasis
certainly complicates control,  but  increases in prevalence
in the population have far greater iaplications.


          Environmental Healtjj Conditions in E
      The historical  information  sought  for environmental
health conditions in Egypt included the following:

    1) General village sanitation

    2) Rural water supply wastewater practices

    3) Rural nastewater practices
                              66

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   34
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                                                              34
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                                                        •
-------
    4) Rural housing conditions

    5) Refuse or solid waste practices.
      Detailed analytical information on these parameters is
rather limited for Egypt as  a whole.  Several local studies
are available however for the delta and for Old Nubia.  Data
from these studies  have  been  provided in somewhat greater
detail.

      Aain  and  Zaghloul    (1959)   in  1959  reviewed  the
administrative  organization   of   the   EMH  environmental
services but provided little data.   They did point out that
by 1959 protected rural  water  supply  had been provided to
each  village  over  1,200  persons.   Generally,  water was
pumped from an  underground  source  to elevated tanks which
supplied a limited nuaber of public water standpipes  (one or
more taps fixed to  a  vertical  concrete slab).  This water
supply project had been  started  in  the 1940's and by 1960
fairly wide coverage was obtained.  In 1975 all villages had
at least one protected  source  of  water.    The goal of one
standpipe per 300 persons was  90-95% completed by this time
(Furnia, 1975).  This is  very impressive when compared with
the water supplies available in  the rural villages of other
similar developing countries.   Installation  of latrines in
the rural areas has been less successful (Furnia, 1975).

      The  aajor  refuse  problem  in  Egyptian  villages is
animal waste (Headlee,  1933;  Meir,  et aT. (1952).  Animal
manure is still commonly used for composting and for cooking
fuel.  The compost heaps and  the  drying dung cakes cause a
serious sanitation problem by  providing ample sites for fly
breeding.   For  the   most   part,   solid   waste  in  the
conventional western sense does  not exist in Egyptian rural
villages.  Only  infrequent  isolated  litter  piles  may be
noted  in  typical  villages.  However,  where  multistoried
housing projects have  been  constructed  and in urban areas
there are extensive  solid  waste  problems.  On the village
level very little  solid  non-organic material is discarded,
This picture  is  now  beginning  to  slowly  change  as the
population grows and as more consumer goods become available
to the rural populations.

      Focusing on the  delta,  Headlee (1933), made detailed
environmental observations on  the  rural village of Rushdy,
Qalyubia.  No clinical data were provided but excellent maps
were made  showing  the  defecation  sites  in  the village.
Samples  were  taken  from  these  sites  and  examined  for
helminthic  parasites.    En terob ijj s,   Ascaris,  Trichuris,
BO§52i§£i§» an<^ &££2i°§i5I§  were  detected in the samples.
Defecation habits did not center  around any favored site in
the village area but  were scattered throughout.  This habit
of "indiscriminate" defecation  at many different locations,
                              69

-------
locations which often provides!  little or ao shelter, rather
than at isolated places (for  example, pala stands)  was also
observed by Scott (1937).

      According to Scott  (1937),  this indiscriminate habit
has important implications concerning hookworm transmission.
If the same defecation  sites  were frequented then hookworm
transmission would  be  favored,    However, defecation sites
were scattered and,  as  Scott  (1937) showed, the prevalence
of hookworm was not  as high as might be expected.

      Headlee (1933)  also observed the still common practice
of disposing household wastewater in the village streets and
that  the  presence   of  a   stable  attached  to  the  hone
contributed  to  the   intense   fly  problem.   Farooq,  et
alj. (1966a)  commented  that  village conditions in the delta
had changed little since Headlee's report.

      «eir, et al^'s  (1952)  study (1952)  of the same general
area  (Sindbis,  Qalyubia)   confirmed Headlee's observations.
Heir et al.. (1952)  also found  that  31% of all the homes in
the study area had latrines  out  of a total of 4,878 houses
examined, and 13% had wells,   Flies  in the study site were
noted in large numbers,  counts were made monthly on the fly
populations.  These counts showed seasonal fluctuations with
lew numbers in the middle  winter months and high counts for
the remainder of the  year.   Measures  were taken to reduce
the fly populations,  and  it  is  interesting  to note that
during a two  year  period  in  the  areas where control was
maintained, infant mortality was  markedly reduced.   This is
a  very  important   observation.   No  other  environmental
measure   tested   during   this   study   demonstrated  any
improvement in infant mortality,  indicating the overwhelming
importance  of  flies   as   vectors  of  serious  infantile
diseases.

      In 1966, Faroog, et  al..   (1966a), found that 87.6% of
the people in Beheria, in the north western delta, had piped
water, a 7751 increase in  the  number with piped water since
1952.  The  exact  distribution  of  people  with or without
piped water is shown in Table 21.  Ten and a half percent of
the sample used canal water exclusively.

      Table 22, reproduced  from  Faroog's  study, shows the
number and distribution of  people  by type of house.  There
were  considerable  differences  between  divisions  with an
overall 50.5% living in  stone  or redbrick houses and 40.3%
living in mud or  mud  brick  houses.  Farooq, et §JL._  (1966)
also determined the number of persons with a cowshed and the
number and distribution of  latrines.   They found that just
over half of the population do not have cowsheds, 32.9% have
adjoining cowsheds,  and 14.4%  have separated cowsheds.  The
latter group were  considered  to  be  in  a higher economic
class than the former two.  At  these study sites 52% of the
                             70

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                          Table 21
                  Distribution of Exaained
            Population by Source of Hater Supply.
                After Farooq, et ajU  (1966).

Hater
Supply
Canal
Piped iater
Other
Not stated
Total

Number
of People
1248
10466
70
160
11944

Percentage
Distribution
10.5
87.6
0.6
1.3
100.0
population was found to have  latrines; "\Q% had latrines and
did not use thea.   (It would be interesting to know just how
this was determined.)  36.4%  did  not have a latrine.  This
indicates  that  there  is  an  increase  in  the  number of
latrines in the hoses since Weir, et al^'s (1952)  time.
                          Table 22
             Distribution of Examined Population
                     by Type of Housing.
                 After Farooq et alA  (1966a)

Type of
House
Stone or Red Brick
Hud brick or mud
Other
Not Stated

Number
of People
6988
4811
7
138

Percentage
Distribution
58.5
40. 3
0.0
1.5
         Total                11944            100.0
                              71

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      As shown in  the  previous sections on schistosomiasis
all  the  above   environmental  parameters  influenced  the
transmission of infection,  with  the  exception of latrines
which showed a  marginal  decrease  in  prevalence, and only
when age and type of house were controlled for.

      In Upper-Middle  Egypt  only  the  report  by Hassouma
(1975) is available on a  rural housing survey.  Table 23 is
reproduced from  this  report  to  the  Egyptian Ministry of
Planning.  A  majority  of  the  houses  obtained water from
public  standpipes  (5*4%)  .   However,  a  significant number
(14%) had water piped to  the  home.   For 12% of the homes,
water came from the canals.
                          Table 23
         Hater and Waste-Water Facilities in Upper-
            Middle Egypt.  After Hassousa (1975).
                        ifater Supply
      Type of
      Facility
  Piped Inside
  Piped Outside
  Hand Puffip Inside
  Canal
Village
Faraskour
1
36
106
120
2
%
13.
40.
45.
0.

6
2
4
8
Oueaa
f
4
194
8
54
X
1
74
3
20

.6
.6
.0
.8
Deshna
f
48
54
8
24
%
35.
40.
6.
17.

8
3
0
9
                    Haste-Water Disposal
Sewer
Septic Tank
Latrine
None
34
94
134
264
6.5
1.8
25.5
50.2
4
8
219
260
0.8
1.6
36.9
531
44
38
46
134
16. 7
14.5
17.6
51. 1
      Hassouma  (1975) also  found  that  6.4$  of the houses
were converted  to  sewage  systems  and  that  10? had septic
tanks.   These  fascinating   observations,  especially  the
presence of the sewage  systems,  beg the question "what did
the author use  as  a definition of 'rural1?'1   Unfortunately,
no answer was provided.   However,  over  half of the houses
surveyed did not have a latrine.
      Upper Egypt:  in  the
area
72
between Assyut and Aswan,

-------
only sketchy information  exists  and  most  of what does is
centered on the Aswan environment  only,  In 1965 Aswan City
bad no sewage  system  and  the  large fertilizer plant  (The
Kiaa  Company)    nearby   was   inadequately   treating  its
wastewater  which  was   being   discharged  into  the  Nile
(Messina,  1970).   Others  (Bachmann,  1965;  Satti,  1970)
reporting to  the  WHO  found  the  Aswan  urban area poorly
developed ic respect to wastewater management.

      Old Nubia:  In 1960 Abdady and Shalash (1966)  from the
National Research Center, Cairo, completed a one-year survey
on the Nubians which  examined the environment and livestock
resources.  Selection of  families  was  based on the family
register at each village  and selections were representative
and proportional to the 1960 census.  It was a well-designed
study.  Each tribe was  represented  and  Table 24 shows the
number of  families  selected,  by  tribe,  village, and the
location of the village  on  the  eastern or western bank of
the Nile.  Table 25  shows  the  housing conditions for each
area.  Table 26 shows the type of water supply, lighting and
food storage in the  house.   Hhereas  this table points out
that no sewage  system  existed,  the general description of
the text stated that toilets  were located inside the houses
in the Fediga area,  and  outside  for the other two tribes.
Nc numbers were provided  on  how many were available.  Also
included in  this  discussion  was  that  the hand pumpwells
located in the Fadiga area usually did not function,
                          Table 24
            Tribe, location. Village, and Number
             of Families Selected in Nubia, 1960
               After Abdady and Shalosh  (1966)
   Tribe
location on
 Nile Bank
Village
    Number of
Families Selected
fadiga
Fadiga
Arab
Arab
Kanoose
Kanoose
West
East
West
East
Hest
East
Ballana
Abu Simbel
As-Sabuf a
As-Sangari
Sarf -Hussein
Kask Taana
275
170
75
75
75
75
      In the following villages, irrigation pumps and canals
had been installed:
      a)  Dikka
                             73

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74

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                          Table 26
        Water Supply and Lighting in Old Nubia, 1960.
              After Abdady and Shalash (1966).
                  Hater Source            Lighting
Tribe
Fadiga
Arab
Kanoose
Snail
Canals
94
0
0
Nile
275
93
10
Pump
76
57
140
Electric
0
0
0
Kerosene
445
150
150
      b)   Al-Alaqi

      c)   Aniba

      d)   Tushka

      e)   Araina

      f)   Atu Simbel

      g)   Ballana
      A description of the village areas was included in the
report.  In the  Fadiga  tribal  areas,  houses were in rows
with 20-30 meters from  one  row  to the next, spreading out
over a 500 by 600  meter  area.  Houses made of combinations
of aud, rock, and  cane  were architecturally similar to the
American Indian hogan with  walls extending out to encompass
a courtyard, a guest  room,  and a stable.  A characteristic
feature of Nubian  houses  is  the  decoration of the walls,
both on  the  inside  and  outside.   There  is a prevailing
attitude throughout Egypt that the Nubians are exceptionally
tidy and hocest.

      Floor  plans  of  the  old  Nubian  houses  have  been
prepared fcy Fernea (1573).

      In brief, Egypt  has  had  a  progressive plan for the
provision of a  protected  water  supply  to the rural areas
since the  19i40*s.   A  visit  to  the  rural  areas readily
confirms the widespread distribution  of rural water supply.
This project has  probably  reduced  the  numbers of persons
visiting  canals  or  unprotected  water  courses  for their
                              / ^}

-------
water, but still evident  io  the  rural areas are the women
washing clothes  and  dishes  in  the  canals,  the children
bathing in the canals, and  the farmer irrigating his fields
by  ancient  methods  requiring  contact  with  canal water.
Generally the sanitation conditions in the villages of Egypt
have improved  somewhat  since  Headlee's  study (1933).  In
terms of crowding, they may have become worse.
                             76

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                         CHAPTEB III
                    MATERIALS AND METHODS
      This study is  separated  into two najor subdivisions.
The first, termed the "downstream  study" is a comparison of
environmental  and  epideaiological   health  parameters  at
different  village  sites   comprised  of  indigenous  rural
populations located downstream  froa  the AHD, excluding the
relocated Nubians.  The second, termed the "Nubian study" is
concerned  with  the  Nubian  populations  displaced  by the
formation   of   Lake   Nasser,    The   results   of   both
investigations  have  been  analyzed  for  correlations with
environmental and epideaiological alterations resulting from
the construction of the AHD.   In both studies, the research
is guided by an operational hypothesis.


            Description oj the !LDpj*nstreaj|
      The downstreaa study is  designed to assess the impact
of  the  formation  of   lake  nasser  on  indigenous  rural
populations in Egypt  downstream  from  the AHD,  The design
rationale is based on a  comparative approach for which data
are collected froa  more  than  one  site.   Thus  it can be
deteruined whether changes occurring  overtime or in a given
location  are  unique,  and   causal  relationships  can  be
developed accordingly.

      Three areas have  been  selected  which afford maximum
comparability.   The  first,  fron  an  area  likely  to  be
affected by Lake Nasser, are the rural villages north of the
city of Aswan and south  of  Kom  Otabo.  The two other areas
are Beni Suef, between  the  delta  and  Assyut, and Kafr El
Sheikh, in the north  central  Nile  Delta.  For the sake of
convenience, the three "areas"  in which rural villages were
selected for the  downstream  study  are  referred to as the
Aswan, Beni Suef, or Kafr El Sheikh study area,

      In each of  these  three  governorates, rural villages
have been  selected  based  on:  a)   how  representative the
village is  of  the  area;  b)   accessibility; c)  population
composition and size; d) the  presence or absence of a rural
health center or unit.  The selection of villages from these
three areas was also based on information obtained from past
                             77

-------
studies.  It was clear  from these studies that Upper-Middle
and Upper Egypt  had  frequently  been  excluded, with a far
greater number of  past  surveys  being  carried  out in the
delta.  Bithin  the  delta,  more  prevalence information on
schistosoaiasis was  available  for  Qalyubia  than  all the
other delta gcvernorates combined.   Sites in Kafr El Sheikh
were selected, therefore, to help correct this deficiency of
information,   Also,  historical  data  indicated  that  the
northern delta, in  which  Kafr  El  Sheikh  is located, had
maintained  the  highest  schistosome  prevalence  in  rural
Egypt.  The data frou  Karr  El Sheikh provided the ultimate
baseline prevalence  for  this  study,  as  opposed to areas
farther south  and  geographically,  more central.  Villages
were selected in  the  Beni  Suef  area as representative of
Upper-Middle Egypt, for the  simple  reason that recent data
indicated that  the  distribution  of  S± jansoni. infections
were slowly migrating south,  from  the Mile Delta into this
area  (Hussein, 1972, Alamy and Cline, 1977).  Sporadic cases
°f J,t Jlflsoni had been seec  in Beni Suef by Hussein (1972).
It was therefore important to  determine if S_. l^asoni cases
could still be found or were increasing.
                          of the "Nubian gtudy"


      This study is designed  to  aeasure the changes ia the
prevalence  of  schistosomiasis  in  the  Nubian  population
fcllowing displacement due to  the formation of Lake Nasser.
The Egyptian  Nubians,  a  population  of 45-50,000 persons,
resided in villages scattered  along  the banks of the Nile,
south of Aswan to the  Egyptian border.  This population was
displaced by the rising waters of the new lake in 1964.  The
Nubians, who were  rural  in  nature  and  composed of three
different tribes were moved  en  masse  to  Kom Ombo, 40 kms
downstream from the  AHD,   For  all practical purposes, the
entire population  was  resettled  in  this  area.   The new
villages  bear  the  same  names  as  those  from  which the
settlers originally  came  and,  in  addition,  retain taeir
respective locations as in old  Nubia with the Kanoose tribe
in the north, the Arab in  the middle, and the Fediga in the
south  (See previous Figure 11).  No other formal arrangement
was made by the  government  to  have resettlements in other
areas.  However, there remains  an original Nubian community
located on the  eastern  Nile  bank,  just  north of the old
Aswan dam, called  Kazan  Sharg.   This  is the southernmost
village in Egypt with the  exception of a very small village
located on an  island  in  the  reservoir that inundates the
area between the old  and  new  dams.  No resettlement sites
are present on the lake  shore.  The high ground surrounding
the lake  is  harsh,  barren,  and,  according  to  Dazo and
Biles's (1971) survey,  uninhabited,  with  the exception of
the Abu Simbel  community  300  kms  upstream  from the AHD.
                             78

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Although Abu Simbel does not constitute a rural/agricultural
community,  it  is  the   only  permanent  lake  shore  site
currently inhabited,  In 1S71,  the population of Abu Sicabel
was 131  and  was  comprised  mostly  of  government workers
employed in the maintenance of  the Abu Simbel temples.  Abu
Simbel does not represent  displaced Nubian communities, but
is the only location that  could possibly give an indication
of  the  current  health   conditions  at  the  lake  shore,
Observations nade during a  five-day  trip on Lake Nasser in
May, 1977 confirmed these  findings.   Earlier in the Review
of Literature, Dazo and  Biles  (1972)   found that 9% of the
population there had  S..   ^^eMi°MiS infections.  No other
helminthic infections were observed.

      The Nubian study  includes  three  aajor sites between
which comparative studies  have  been  aade:  a)  the old, no
longer existing  Nubian  villages  of  Kurta,  El Malki, and
Ballana; b) the correspondingly resettled sites at Kom Ombo;
and c)  the original  Nubian  community, Kazan Sharq, located
on the eastern Nile bank just north of the old Aswan Daa.

      Abu Sinbel had  to  be  excluded  because  it does not
represent the Nubian population.  Also excluded are the lake
shore sites which  are  yet  to  be  developed, and the Lake
Nasser fisheraen.  As mentioned  previously, a joint WHO-EHH
inter-region project (18-065  RDF/71/217)  is currently being
organized to  investigate  the  health  status  of  the Lake
Nasser fisberaai; population.
      The working hypotheses  from  which  the survey design
has been developed are:

      1) The  Downstream   Study;   There   are  significant
         increases   in   the    estimated   prevalence   of
         schistosomiasis  due  to  the  construction  of the
         Aswan High Dam and  related irrigation expansion in
         the sample of  the  selected  sites  located in the
         Nile Delta, Upper-Middle, and Upper Egypt.

      2) The Nubian Study;  There  are significant increases
         in the estimated  prevalence of schistosoraiasis due
         to  the  construction   of   the  AHD  and  related
         irrigation expansion in the  sample of the selected
         sites located in the resettled Nubians in Kom Ombo.

      Definitions for  pre-  and  post-  AHD  are  needed to
establish the  point  in  time  for  describing 'before1 and
•after' conditions necessary  for uaking comparisons between
studies.   Pre-dam  is  defined  as  the  period  before the
discharge of the Nile  was  controlled by the AHD.  Post-dam
                             79

-------
is defined as the period froa 1964 to the date of this study
(1976).  The construction of the AHD was not completed until
1974, but as mentioned  earlier, the coffer dam, constructed
to divert the flow of  the  river  around the area where the
AHD's foundations were being  laid,  was removed in 1964 and
the ensuing floods have  since  been trapped behind the AHD.
The reservoir  reached  maximum  volume  in  1976.  The term
"significant" is defined  as  a  meaningful  increase in the
prevalence of  schistosomiasis  when  comparing  the results
from  different  study  sites  used  in  this  research with
results  from  other  villages  employed  by  other workers.
Frequently,  the  nuaber  of   cases   is  large  enough  to
demonstrate   statistical   significance   between   results
differing orly in  one  or  two  percentage points.  Whereas
this would constitute statistical significance, it would not
be meaningful.  Faroog, et  aJL^,  1966, and others (Bell, et
ajU, 1967, Gilles,  et  ala,~ 1973)   have  shown that on the
average,  the  variation  in  prevalence  of schistosomiasis
from one Egyptian  village  tc  another  is  about  10 to 12
percentage  points.   This  is   a  considerable  amount  of
variation and  is  due  principly  to  the  focal  nature of
schistosoaiasis  distribution  which  has  been consistently
deaonstrat€d  since  the   earlier  studies.   Therefore,  a
significant  or  meaningful  increase  (or  decrease)   would
require at least a difference of 10 percentage points.


                      Data Ac
-------
                                 Collected


         The categories for data which were collected are:

             1)  environmental health parameters:

                a)water supply and use

                b)sewage disposal

                c)housing

                d)irrigation practices

             2)  epidemiological parameters:

                a)age-sex structure of the sample population

                b)schistosomiasis prevalence.

      It nay be  noted  that agricultural irrigation methods
have teen  included  as  an  environmental health parameter.
Generally, irrigation schemes, as  such,  do not fall within
the realm of environmental  health specialties.  However, in
Egypt as in a  number  of other tropical developing nations,
agriculture practices and especially irrigation methods play
a  central  role  in  the  transmission  of schistosomiasis.
Moreover,  it  is  the  open  canals  and  drains  which are
associated with present-day irrigation in Egypt that provide
excellent  habitats  for  snail   vectors.   For  the  rural
populations of Egypt, canals long  ago became a way of life.
The  convenience  the  canals  have  provided  in  the rural
villages for domestic water  for washing, bathing, swimming,
drinking, and  ablutions is readily evident to the visitor.

      Data acquisition forms  (questionnaires)  were designed
and translated into Arabic.  These forms serve as a list for
the various parameters  under  study.    The original English
data forms are included in Appendix 2.

      The environmental  health  parameters  are  a critical
measure under study.   However, the environmental parameters
not  directly  associated   with   water  use  require  some
explanation,  e.g.   housing.    Housing   is  an  important
indicator of the level of  sanitation,  which is an important
variable in this  study.   The  level   of housing conditions
also serves as an indication of environmental changes in the
resettled areas in the Nubian study.

      Considerable  peripheral  data  are  included  in  the
survey listed on the data  forms.   As much data as possible
were obtained concerning all the environmental parameters in
the hope that nothing would  be overlooked simply because it
                             81

-------
was not requested.  Secondly,   data  were needed to control
for certain  variables;  for  example  age, sex, occupation,
etc.  Indeed, the study was originally designed under a much
broader scope specified by the  needs of the River Nile-Lake
Nasser study of which this work was a part,


                         of Field Jurvey_ Sites
      A total of ten health  units and centers were selected
in Kafr  El  Sheikh  and  in  Beai  Suef  based  on criteria
mentioned in the description  of  the downstream study.  The
name of the health unit or center does not always correspond
to the name of the  village from which the sample population
was selected.  Sometimes more  than  one village was sampled
by the health unit or  center.   This is true also for Aswan
acd for the Nubian sites.

      In  Kafr  El  Sheikh  the  selected  health  units  or
centers, also termed "study  sites",  and their code numbers
were:

   (a)  health unit El  Agazein   (16):   only  the village El
       Agazein was sampled;

   (b)  health center El  Hamra   (17):   only  the village El
       Hamra was sampled;

   (c)  health unit Hahalet El  Kasab  (18):  only the village
       Hahalet El Kasab was sampled;

   (d)  health unit tlahalet Mousa  (19):  Mahalet Mousa and El
       Nataf were sampled;

   (e)  health unit  Sheno   (20):   two  villages,  Sheno and
       fieskit El Shenawi, were sampled.

      In Beni Suef, the selected health units or centers and
their code numbers were:

       (a) health  center  Barout  (11):   only  the  village
          Earout was sampled;

       (b) health unit Sherif  Pasha   (12):  only the village
          Sherif Pasha was sampled;

       (c) health unit Naiio   (13) :    two villages, El  Aorana
          and Abu Mousa were sampled;

       (d) health center Beni Adi  (14):  only the village of
          Beni Adi was sampled.

       (e) health center Ashamant  (15):   only the village of
                              82

-------
          Ashamant was sampled.

     Both Kafr El Sheikh  and  Beni  Suef are the respective
capitals of their governorates.  Kafr El Sheikh is about 2.5
hours' drive north of Cairo, roughly 1**0 kms, and is located
in the central northern  sector  of the delta.  The northern
border of the Kafr  El  Sheikh province is the Mediterranean
sea.  Almost the same distance to the south of Cairo is Beni
Suef.  To the north of Beni  Suef  is Giza; to the west, the
Fayoum; and  to  the  south,  Minya.   Each  of the villages
selected in  both  Kafr  El  Sheikh  and  Beni  Suef  was an
agricultural community typical of the area.

      In Aswan  the  selected  health  units  or centers and
their code numbers were:

       (a) health  unit  Kazan  Sharg  (1) :   the  village of
          Kakhor was sampled;

       (b) health  unit  Guzaria  (2):   the  villages Gamma,
          Oarob, and Harrob were sampled;

       (c) health center Abu 8ish Eahri (3) :  the villages of
          Mai Katta and Mai Licta were sampled;

       (d) health  unit  Ga'afra  (4):   the  villages  of El
          Aratag, Shouna,  Masagien,  Falaleha,  Onarab, Ali
          Abu Kariae, El Sheikh  Garat, Hedadoun, Hagar, and
          Bahatta were all sampled;

       (e) health  center  Biaban    (10):    the  villages  of
          Kenisa, Abu Snarl, Omda, Mariab, Sheikh Mousa, and
          Katarra were all sampled,

      In the  Nubian  resettlement  area  of  Kom  Ombo, the
selected health  units  or  centers  and  their code numbers
were:

       (a) health  center  Ballana   (5):    the  villages  of
          Ballana 1,2, and 3 were sampled:

       (b) health unit Tushka   (6) :   only the village Tushka
          was sampled;

       (c) health center El Malki  (7):   only the village of
          El Maiki was sampled;

       (d) health unit Kurta (8) :   only  the village Kurta 2
          was sampled;

       (e) health center Kalabsha (9) :  the villages Kalabsha
          and Abu Khor were sampled.

      The location of  the  different  selected sites in the
                              83

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Aswan study area can be  seen  on  the sketched map given in
Jigure 14.  The village  of  Kazan  Sharg  (1) is one of the
most southern villages to  be  found in Egypt.  This village
is conprised of Nubians of  the Kanoose tribe, and it should
be pointed out  that  Kazan  Sharg  (1)  and a few remaining
villages just to the  north,  are  also populated by Nubians
who, because of their location  downstream from the AHD, did
not have to be moved when Lake Nasser began to fill. Rather,
this small population  of  Nubians  are  living  in the same
villages and the saae homes  that they were living in before
the AHD  was  built,  or,  for  that  matter,  from the last
century and before.

      The villages located at  health units and centers 2,3,
and H are ccmnunities typical  of the area between Aswan and
the Ron Onbo plain and  are  located  on the eastern bank of
the Nile.  These communities are characteristically found on
high, dry, barren  ground.   Because  the  Nile Valley is so
narrow in  this  area,  very  little  land  is available for
cultivation, and, therefore,  what  is  available is far too
valuable to build on.  The cultivated areas are always found
as a green strip between the village and the river, with the
exception of Hagar in  Ga'afra,  which  is  located on a lew
barren hill  next  to  the  river.   In  this  respect these
villages are unlike the  ones  in  the KODJ Oiabo agricultural
plain.  From  the  northern  point  of  the  Koai Ombo plain,
continuing north,  the  narrow  valley  gradually  begins to
widen as it passes  through  the next two governorates, Qena
and Sohag.  In these sites  the  villagers live at a greater
distance  from  the   irrigation   canals  and  drains  than
villagers located in  the  delta  or  in Upper-Middle Egypt.
Villages are found within  the  cropped area  with increasing
frequency as one travels north  and  east of Aswan into Qena
and Sohag.  North  of  Sohag  only  a  small fraction of the
rural population  resides  in  villages  located outside the
cultivated land, and these villages are often bounded on one
side by their fields.   The  health  center Biaban  (10), was
selected to represent  villages  typically  built within the
cultivated area.   Six  different  villages  all  located in
Bimban narkaz   {center)  were  sampled.   The Biffiban jaajcjraz,
seen on the map in Figure 11, is located on the western bank
of the  Nile  Valley  almost  directly  west  of Daraw.  The
villages are separated froa the  Nile and from the desert to
the west by fields  cf  sugar  cane  and  wheat, and by palm
groves, etc.

      The selection of the  Nubian resettlement villages was
based  on  the  previous  study   by  Zawahry   (1964).  Each
village that was  surveyed  in  1964  has  now been surveyed
again for this  study,   They  are  Ballana  (Fadiga)  (5), El
Kalki  (Arab)  (7), and Kurta  (Kanoose)  (8).  In addition two
other  villages  were  selected:  Tushka  (Fadiga)   (6)  and
Kalabsha  (Kanoose)  (9), to increase the overall sample size.

                             84

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              EL SIBAYA'
                                 SILWA 8AHARI
                                   O
                                          MAP SHOWING LOCATION
                                        OF ASWAN GOVERNORATE
                                           HEALTH SERVICES
                                           SCALE Ml 500 000
                                                  Q PRIMARY HEALTH UNIT
                                                  SECONDARY HEALTH UNIT
                    EL
                    Low Dom-f'iy* EL SHATTAL
Figure  14.   This is a sketch map of the  Kom Ombo area showing the
distribution of health units and centers.   Also shown are  the
study site  locations for  this area, which  are represented  by the
shaded  units.
                                 85

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                    Data Collection Teams
      The primary  data  collection  teams  at  each  of the
selected   health  units  or  centers  were  comprised  of a
physician, a laboratory technician, a sanitarian, one or two
ncrses, and one or  iiore  aides.   The  team  was led by the
physician  whose   responsibility   was   to  implement  the
collection of data and  to  ensure  that all activities were
completed according to the outlined procedures (see Appendix
4),  The cooperation  and  employment  of the various health
teaas was obtained through  the  Egyptian Minister of Health
and through the respective regional offices of the director-
general   of   health.     The   director-general   provided
transportation to the  sites  and  local security approvals,
and saw to it that  the materials necessary to continue were
received  at  the  study   sites.    In  addition,  a  field
supervisor, typically a  vice-director-general, was assigned
to follow the day-to-day progress  in  the field and to work
closely with the  technical  field  supervisor (the writer) .
Aside  froffl  developing  the  plan  of  operation, acguiring
materials, and training personnel, the role of the technical
field supervisor was to coordinate the work at all levels at
each of the twenty field sites.

      The Egyptian  Minister  of  Health  assigned  Dr. Baha
Hashen, the director-general of all rural health services as
a tcaa representative froa the ministry to the project.  The
EHH's services proved  to  be  very  helpful in establishing
communications, transporting materials, collecting data, and
obtaining cooperation of primary data collection teams.

      The chief administrative team  leader. Dr. M. Hussein,
Dean  of  the  High  Institute   of  Public  Health  at  the
University  of   Alexandria   developed  the  administrative
structure by which the  various  data teams and members were
e»ployed and  paid,  and  closely  followed  the  day to day
developments  in  the  field.   In  addition,  Dr.   Hussein
obtained the  necessary  governorate  approvals and security
permits and provided the  laboratory space and personnel for
the  analysis  of  the  stool  and  urine  specimens  at the
University of Alexandria,
        .SiSJ! of Facilities and £rep_aration of Material
      The location for  the  examination  of  families was a
rural health unit  or  a  rural  health center.  Each health
unit  (for outpatients  only)  and  each health center (small
scale in-patient facilities available) selected was assessed
for facilities  needed  for  the  survey.  If  facilities or
equipment were  lacking,  they  were  obtained  by the local
field  supervisor  from  the  respective  director-general's

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office.  For the most part these services were not needed as
the health units and  centers  selected all had the required
facilities and  were  in  working  order.   These facilities
included:

       
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forms coded 03 through 12.   (All data forms and the methods
guide  are  included   in   Appendix   2   and  Appendix  3,
respectively.)   The  translated  forms  were  reproduced by
mimeograph,  at the  beginning  of  the field activities all
forms  were  reproduced  at  the  High  Institute  of Public
Health,  Over 8,000 forms of  01 and 02 were necessary.  Form
01 had  three  pages  and  02  had  four.   Therefore, 56,000
sheets of paper were required  just for these two forms.  It
scon became obvious that  delays  would develop if the forms
continued to fce niueographed  at the High  Institute.  Paper,
stencils, and staplers were  purchased  and delivered to the
local  director-generals*  offices,   which  took  over  the
responsibility of providing printed forms.

      Data form design:  the  data forms for the examination
of the family were based  in  part  on the studies by Faroog
and Nielsen (1966), Zawahry  (1963), and Hussein (1972).  At
each health unit a guide  for  the correct completion of the
data form from the  examination  of the family was provided.
This guide also  included  the  correct  method by which all
procedures were to  be  carried  out  for  the collection of
field data.  The guide  served  only  as a reference and was
not a substitute for instruction.

      It  should  be  pointed  out,  however,  that  special
procedures *ere taken  to  determine age.   The determination
of age in a highly  illiterate population is prone to error.
Measures to miniaize errors  were adapted from Scott (1937).
Scott  (1937) found  that  it  was  more  accurate to place a
person in an age-group  than  to estimate the person's exact
age.  An age group sheet of 5-year age groups  (starting from
0-1) was distributed with  the methods guide and instruction
for use  was  given  to  the  physician.   Birth  dates were
recorded only when government  identification cards could be
provided.

      An attempt was also made to determine what medication,
if any, the individual had taken in the 360 day period prior
to the day of  examination.   Only medications for parasitic
diseases  were  recorded.   Other  medication  received  was
r€corded as "ether".  Details  for  the methods of obtaining
the remaining data and data for the housing are described in
the methods guide.

      The design for  the  housing  form  code number 02 was
adapted  frcn  Mitwally  and  Shargawi's   (1970)  article on
measuring housing conditions  in  the  rural areas of Egypt.
For each data form  a  clear  plastic  overlay sheet with an
English translation was made.  These clear overlays provided
ar instant translation of the Arabic data form into English.
As a guideline, the house  to  be examined by the sanitarian
was defined as Mthe area lived  ia by the selected family".

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          Ereservat-ion of Stool and Urine Sgecigens
      It  was  clear  from  the  beginning  that  there  was
considerable variation in ability to examine stool specimens
for parasites and ova  between laboratory technicians at the
selected health units  and  centers.   To compensate for the
undesirable variability  and  to  maximize the comparability
from one study  site  to  another  all  stool specimens were
preserved and sent to the  laboratory at the High Institute.
At the "central laboratory" the specimens were examined by a
staff of trained personnel.

      To iiplement this central approach for the examination
of the specimens,  a  10  ml translucent polyethylene bottle
was provided  for  each  individual  at  the selected sites.
These bottles were  purchased  in  Cairo  and  were  2 cm in
diameter, 5 cm tall with a 1 cm opening in the top for which
there  was  ao  inner   cap   and  an  outer  screw  cap,all
polyethylene.   On  each  bottle  the  code  number  of  the
individual, comprised of the  health unit number, the family
code number, and the  individual's  number within the family
and his or  her  name  were  written  with black, permanent,
felt-tipped pens.  Both pens and bottles performed well over
the period cf the  survey.   There  was no occasion when the
label came off, and the bottles, which were unbreakable, did
net leak  even  though  an  occasional  screw  top  had been
deformed during the nolding process.

      The procedure for collecting  the  stool and urine for
preservation is outlined in  the  methods guide.  Two points
should  be  added.   One,  that  the  urine  specimens  were
examined at the health  units by the laboratory technicians.
In addition, two drops  of  urine  sediment was added to the
stool specimen for preservation and examination later at the
central laboratory.  In this way a double check was provided
on the examination of  urine,   The  results  of the on site
examination  were  recorded  on   the   data  form  for  the
examination of the family,  fora  01.   Two, the transfer of
the stool from the stool pan  to the specimen bottle and the
mixing of the stool  with the preservative solution required
something cheap and  disposable.   Broom  straws, along with
matchsticks and toothpicks,  were all tested unsuccessfully.
Very commaon in  Egypt  are  small  vegetable crates made fcy
hand from palm fronds.  The  ribs of these crates were found
to split nicely  into  straight  wooden  sticks which easily
transferred and mixed the  specimens.  For preservation, the
stool was mixed with  9.0  to 9.5 cc of merthiolate-formalin
solution   adapted   from   the  merthiolate-iodine-formalin
concentration technique (MIFC)  (Blagg,  et a_lA, 1955).   Ova,
cysts, and trophozoites  in  fresh stool specimens collected
in the MIF solution have been successfully preserved without
deterioration  cf  descriptive  cytological  features  for a
number of  years.   The  exact  per-cd  before deterioration
                             89

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begins is under study at the Naval American Medical Research
Dnit  (NABBU-3)  in  Cairo  where  the  technique  was first
developed.  Instead of adding iodine (Lugol's iodine)  at the
time  of  preparation  when   the  specimen  was  mixed,  as
prescribed by this technique,  the  Lugol's iodine was added
afterwards at the central  laboratory  just before the ether
extraction phase.  This alteration in technique, in addition
to the fact that approximately 0.05 ml of urine sediment was
being added, did  not  interfere  with  the desired staining
intensity.  By delaying  the  addition  of Lugol's iodine at
the health unit or center,  the amount of materials that had
to be delivered  was  reduced.   This  also assured that the
Lugol's solution used was fresh, as it begins to deteriorate
as a stain  after  one  week.   Thus  the urine was examined
twice, once at the  health  unit  or  center and once at the
central laboratory.


                      &£ sLtool and Urine Specimens
      All specimens were  collected  from  each of the study
sites and transported to  the parasitology laboratory at the
High Institute of Public Health.   At the laboratory, a team
comprised of nine  physicians  examined  the specimens.  The
team  was   supervised   by   three   senior   lecturers  of
parasitology at the High Institute.

      All  specimens  received  at  the  laboratory  froa  a
particular health  unit  or  center  were  grouped together.
There was no  intended  order  within  the  group  and a few
specimens at a time were  selected for examination from each
group.  This quasi-random method helped minimize the biasing
effect of individual ability among the laboratory personnel.

      The preparation of a  specimen  for examination was as
follows:

  1) the specimen was mixed  and   poured  through a layer of
     wet gauze into a labelled centrifuge tube.

  2) 0.6  ml  of  fresh  Lugol's   iodine  was  added  to the
     specimen.

  3) i» ml of petroleum ether  added in order to increase the
     specific gravity of the ova   and cyst by extracting the
     lipid  fraction.   The  tube  was  inverted  and shaken
     vigorously,

  4) the specimen was centrifuged  for 5 minutes at 1500 rpm.

  5) the top ether layer and  fecal plug, and MIF layer were
     removed by suction, leaving   the sediment and about 0.1
     ml of KIF solution on top of  the sediment.
                              90

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  6)  the sediment was resuspeiided and a drop of this mixture
     placed on a microscope slide,  and covered with a cover
     slip.

  7)  the slide was  examined  for characteristic ova, cysts,
     and trophozoites.

  8)   results were entered  on  a coded specimen examination
      fora, an example of which is shewn below.

      Sto_ol examination form ICode _51_

      Specimen vial number

      Date

      Helminths

      Ascaris lumbricoides....	..1
      Trichuris trichiura............................2
      Entercbius venicularis.	....3
      Ancylcstona duodenale	................ U
      Strongyloides stercoralis......................5
      Taenia sp	.........6
      Trichostrongylus sp.	 7
      H. nana,.	......8
      H. heterophyes,	..........9
      F. hepatica..	.......10
      F. gigantica	11
      S. haematobiuB............. .................. .12
      S. mansoni.	..........13

      Protozoans
      Giardia lamblia.	.........14
      E. histolytica.....	.... .		15
      E. coli	....16
      E. hartmanni.	..17
      Iodamoeba butschlii	..18
      Endolimax nana.	.......19
      Chilcsastix raesnili......	...............20
      Trichomonas ho sin is.....	21
      Dientamoeba fragilis	22
      Examined by,
      The coded specimen form includes  a place for the code
numbers, date, form code, and code number of the examiner at
the  laboratory  who  txaained  the  slide  and  places  for
indicating the presence  of  the various parasites screened.
Only one slide for each specimen was examined.

      An in-laboratory  test  was  used  to  obtain  data on
individual  examiner  error.   One  specimen  each  day  was
examined   fcy   all   membersq, and   the   results   scored

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independently.  It was requested  that the personnel examine
the "test" Elide in  the  same  fashion as all other slides.
The exaa results were not shown to the personnel, and it was
emphasized that  this  was  a  procedure  to  estimate error
rather  than  a  proficiency  examination.   All  laboratory
personnel at the  High  Institute  were closely followed and
exhibited proficiency xn  the  identification of the various
parasites.  The helminth ova  are  easy  to identify as they
are generally large, and  very characteristic in morphology,
Proficiency was assured  by  comparing sample specimens with
the NAMRU-3 laboratory.

      An examination of the  urine specimens for schistosome
ova was  also  completed  at  the  health  unit  or center's
laboratory.  The  method  used  was  the  simple and classic
sedimentation  technique.   This  is  the  same  method most
commonly used in screening procedures where large numbers of
specimens have to be examined and is described by Farooq and
Nielsen (1966).   Briefly,  urine  is  placed  in  a  300 ml
conical flask  and  left  undisturbed  for  30 minutes.  The
sediment  is  then  transferred  to  a  slide,  covered, and
scanned for ova under  low  power.   This technique has been
used in Egypt  for  a  long  time.   None  of the laboratory
technicians  at  the  health  units  or  centers  had  to be
retrained and  uany  were  eager  to  display  their skills.
Nevertheless, the physician was  placed  in direct charge of
insuring that correct procedures  were adhered to.  With one
exception, there was never  an  occasion wheu the results of
the  laboratory  technicians  were  in  question.   The  one
exception, in Bimban  (10), is elaborated on in the Rtsults.


                       of .the SajB£le Population
      A systematic sample was taken at each study site.  The
unit of  selection  was  the  family.   All  members of each
family in the sample  were  examined.   Prom each study site
about 200 families were  selected systematically from a list
drawn up from the   village  or  villages to be sampled that
included all the families of the village or villages and all
the members of each  family.   By selecting 200 families per
health unit or center,  a  sample total of approximately 700
to 900 persons was  estimated.   The  target sample size for
all study sites  in  both  studies  was between fourteen and
eighteen thousand.  The family  list was the sampling frame.
For purposes of  selecting  the  sampling unit  (the family),
the family was defined as a  man, his wife or wives, and all
SSS§£jiS^ offspring.  This  definition  was  easy to use and
fairly stable,  i.e.,  the  average  number  of  persons per
family did not vary  greatly  from  site  to site, though in
Upper Egypt the families  were somewhat smaller.   (Note that
net all offspring of a selected married female  may have been
examined.)  All selected family  members were accounted for.
                             92

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If a member did  not  attend the examination, an explanation
of why the nernber was  not  present was stated on the family
examination form,  No attempt was  made to replace those who
would not cone, were absent  at  the  time of the survey, or
had died.

      To make the selection  of  the families, an up-to-date
list of family  names  and  members,  or sampling frame, was
required.  Generally a frame was available but often out-of-
date by four to five years.   In order to avoid delaying the
start  of   the   survey,   the   following   procedure  was
isplemented.  The total number  of  families in the old list
was divided by 200.   The  number obtained, for example 3.4,
was rounded off to the  next  hicjher number and added to one
(2 or 3 in ether cases  depending on an estimate of how many
new families  would  be  added).   In  this  example, with a
starting list of 680,  every  fifth fa«ily would be selected
starting from a random  number  between  1 and 5.  The frame
would immediately begin to  be  updated, adding new families
at the end of the list,  and the examination of the selected
families starting  from  the  first  selected and proceeding
seguentially  was  also  begun.   The  up-dating  was always
finished long before the  examination of the first selection
of families  could  be  completed.   The  selection of every
fifth family according to  this  example  would result in an
under-selection, i.e. less than  200  would be selected.  In
this case about 136  families  would  be selected if 120 new
families were added to the  original list of 680.  After the
examination of 136 families,  64  families  would have to be
reselected  from  664   remaining   unselected  families  by
selecting every 10th family.  Beselection being made without
replacement, a total of  202  families would be selected and
examined.  This approach was used throughout the study, with
two or more  samples  (one  or  more reselections)  from each
site being taken in this  fashion.  Each selected family was
circled and serially numbered  in  the  list of family names
and members.

      The serial number  for  the  family  became the serial
code number for that family.  The members of the family were
listed serially starting with  the  first person examined on
the  family  examination  data,  form  01.   This  gave each
individual that was  examined  in  the  survey a unique code
number comprised of the  numoer  of  the village, the family
serial code number,  and  the  individual code number within
the family.  The code  number 01,001,01 identifies the first
person in the first family  selected  at the health unit 01,
Kazan Sharg.  The health unit  or center code number and the
family serial code  number  were  used  to identify the data
forms 01 and the housing data  forms 02.  The data form, 02,
was  completed  for  each  house  of  each  of  the selected
families.  These forms were matched with the family 01 forms
by coding  the  02  forms  with  the  health  unit or center
number, the house  number,  and  family  serial code number.
                             93

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The same saiapie size (200  families)  was used throughout the
survey, rather  than  selecting  a  given  proportion of vhe
population at each  site.   Therefore, the sampling fraction
varied froa site to site.   This was done for administrative
reasons, and because it  was  desired that the completion of
the survey of the  families  and  the environment be roughly
during the saae period of time at all sites.   The reason for
this was that by  carrying  out  the survey at the different
sites over  the  same  period  of  time,  the possibility of
seasonal variation of  the  parameters  measured between the
sites would be negated.

      It was  estimated  that  200  families  would  yield a
sample of about 800 individuals.   This sample size was felt
sufficient to give the  estimates  of the various parameters
sampled  with  adequate   precision   at   each  site.   The
systetatic selection of families  was  used  as opposed to a
purely random method for  two  reasons.  One, the systematic
selection mere often than not gives greater precision.  With
a systematic selection, no  isolated groups, individuals, or
houses  are  left  unrepresented  in  the  sample,  as might
inadvertently happen  with  a  random  selection.   Two, the
selection of  the  families  for  examination  could proceed
iaiediately without waiting for  an up-dated family list,  A
random sample would be impossible  to select before the list
was completed because the added group would not have a known
possibility of being selected in the first round,
                  o  the Environment and the
      Before the survey  could  begin,  each  health unit or
center  had  to  receive  the  necessary  materials  and the
personnel had to review the  aethcds for the correct filling
in of the data  forms  and  the correct method for preparing
the stool and urine specimens.   The up-datiag of the family
list  was  always  the   first  activity,  followed  by  the
selection  cf  the  families.    In   order  to  obtain  the
cooperation of the village members,  a meeting was held with
the village  council,  the  local  physician  and  the field
supervisor, to explain the purpose of the survey and solicit
the aid of  the  council  to  overcome any difficulties.  On
occasion the  director-general  of  the governorate attended
these meetings.  Only after the personnel at the health unit
or center showed proficiency  with  the different aspects of
the data acquisition was the examination begun.

      Generally  a   routine   was   established  where  the
sanitarian would go to the selected family's house, complete
the bousing form and instruct the family to go to the health
unit or center the following day.  The instructions included
telling the  family  members  that  the information obtained
would be held ia strictest  confidence and that specimens of
                              94

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stool and urine would  be  requested  at  the health unit or
center.  At the health  unit  or center, the selected family
members would be qiven a  numbered  stool pan and a numbered
tin cup and requested to provide  a specimen of each at some
point during the examination.

      By obtaining the  specimens  from  the selected family
members at the health  unit or center, proper identification
of the specimens  could  be  guaranteed.   This  is a unique
feature to this  survey.   Scott   (1937) , Farooq and Nielsen
(1966), and Zawahry  (1963)   all  obtained their specimens by
providing specinen containers to  the heads of the household
of each of the families selected.

      There were exceptions, most  notably   at Kurta (8) in
the  resettled  Nubian  area.    The  water  supply  in  the
laboratory at Kurta  (8) was  the  most inadequate of all the
selected sites.  The piped water supply was limited to a few
hours a day and  frequently  failed  for periods longer than
48  hours.   Water   rarely   came   to  the  health  unit's
laboratory.  At Kurta  (8),  protected  water was used first
for drinking and cocking before it went for other purposes.

      Because  of  this   lack   of   water  at  the  health
unitrselected  family   members   refused   to   give  stool
specimens.  Under the  circumstances,  the  methods of Scott
(1937), Farooq  (1966),  and  Zawahry   (196*)  were employed.
Thus the correct specimen was obtained.  Also, a large metal
reservoir was given to  the  health  unit laboratory so that
water could be stored and available to clean equipment.

      Trips to the field  to  initiate the survey activities
were made ii? early April, 1976.   By May, 1976 all units and
centers had begun the collection  of data.  After the survey
had begun, each field  site  was repeatedly visited.  During
these visits, additional  saterials were supplied, completed
data forms and prepared  specimens  were  picked up, and, if
required, a reselection  was  made.   In  addition, a survey
progress evaluation was made.   This evaluation included the
following:

      1) a check to see if the names on the completed 01 and
         02 forms corresponded  to  the  names in the family
         list.

      2) a check to  see  if  the  correct code numbers were
         being used.

      3) a check to see if  the  code number on the specimen
         bottles corresponded  to  the  code  cumber  on the
         faiily fora 01.

      4) a check to see that the housing forms 02 were being
         correctly completed.   This  was  done by selecting
                             95

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   several completed forms and going to the respective
   hoees and seeing if the completed forms agreed with
   the actual conditions.

 5) a check to see if  all  the families in the  village
   were included in the  family list.  This was  done  by
   going to the village  and  randomly selecting  a house
   to see if the  occupants   were   listed in the book.
   On no occasion was  a family  located that  had not
   been included.  It should  be pointed out that, one,
   the sanitarians are   well-trained  in this respect;
   and two, they were  often  residents of the  village
   who knew  the  villagers   well,  and  were actually
   related to many of them.

 6) to review any problems  or  obstacles being  met and
   to resolve then.

 7) to review the general progress,  and to determine  if
   the health unit or  center  was  on schedule.  Since
   only part of the  working  day could be allotted  to
   the  examination  of  the  family  members   or  the
   environment at the  health  unit or center, it was
   requested that approximately 20  persons per  day,  or
   five to six families,  be  screened at a time.  The
   examination of the  families  and their environment
   at each site  which   was   to  be completed in about
   three months was  actually  95%  complete after five
   months,

 8) to review the method  of examination of the selected
   fanily members.   This  was  done  by observing the
   coapletion  of  the   family   form  01,  with  the
   physician at the  health   unit   or  center during a
   visit when  examinations   were   being  carried out.
   First, a family that  had  been  examined just prior
   to  arrival  was  recalled  and  re-exarained, while
   checking  the  completed   form   for  discrepancies,
   Secondly, the  completion  of  the  family form was
   followed through  on  a   family  who  had  not been
   examined.  This was especially helpful in detecting
   errors  in   obtaining    and  preparing  specimens.
   Idiosyncratic  procedures  were  noted  during this
   time.  Those which did not in themselves affect the
   collection  of   data  were   usually  allowed   to
   continue, as changing procedure would risk  causing
   errors.

 9) confirmation of the methods used at the health  unit
   or center for conpletion   of  the environmental data
   forms  sere reviewed   in   the  same  fashion  as were
   employed for checking the  housing forms.

10) on occasion, persons  or   families would come to the
                        96

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         health unit or center  requesting to be included in
         the examination.  If the  person  was elderly and a
         relative of a selected  family  or a village leader
         who had not been selected, forms were completed and
         specimens taken.  No  code  numbers  apart from the
         health unit number were given to these individuals,
         Data from these forms were not included.

     11) an inventory  of all the materials,

     12) one of the most important  checks was to see if the
         specimens  of  stool   and   urine  were  correctly
         examined, prepared,  and  labelled.   From the very
         first it was stressed that  the right stool and the
         right urine be placed  in  the  right bottle in the
         correct  manner.     {The   correct   procedure  was
         outlined for the laboratory technicians in Arabic.)
         This  procedure  was  reviewed  frequently  at  the
         health units and centers at the time when specimens
         were being provided by the selected individuals.
      For this study,  3859  house  data forms were executed
for the examination of the  dwelling units.  An almost equal
nuaber were completed  for  the  examination  of the family.
About  400  data  forms   were  conpleted  for  the  various
environmental aspects of the  village sites.  Exactly 15,665
stool  speciaens  were  received.   Ultimately,  over 40,000
cards were keypunched.

      When raw data in  these quantities are obtained, major
efforts  have  to  be  made  to  keep  the  data  from being
misplaced, lost,  or  damaged  before  it  can be processed.
This was aggravated by the distances involved between the 20
different study  sites,  as  well  as  by  the  lack of good
coamunicaticn systems.  Invariably staff at the health units
faced problems after actually  starting the survey that were
not anticipated during the  training  phase.  Most often the
problem was solved by a change in coding procedure which did
not affect the final accuracy.   For example: on the housing
form (02), in ac unanticipated situation, the correct answer
required the selection  of  more  than  one number, although
only a single answer had  been anticipated, and only one box
had been provided on  the  data  form.  The examiners simply
wrote in two numbers,  or  whatever the combination may have
been, in the given box.   This alteration was easily handled
when the coding  sheet  was  designed.   The process was not
always  as  uncomplicated  as   this  and  new  combinations
necessitated redesigning the code sheets.

      To ainiiize problems  of  data  management, a complete

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inventory of the  number  and  amount of materials delivered
and received froa  each  study  site  was kept.  Before data
forms  were   accepted,   they   had   to   be  checked  for
completeness, consistency, and accuracy.

      All ccapleted foris were packaged and delivered to the
Cairo  University  Statistics   center.   Code  sheets  were
designed, tested, and  re-designed.   The final coding sheet
for a particular fora was reproduced at the center by offset
printing.

      Before transferring the data  onto  code forms, a code
bcok or code key was  developed  for each type of data form.
The questions on the  family  examination form 01 concerning
diagnosis acd medication received  were the only examples of
truly open guestions, and required continued updating of the
code book.   The  greater  part  of  the  coding  was simply
copying a selected number onto the code sheet.

      Coded data were  verified  on  a  sample of forms from
each site before  punching.   Punching formats were designed
froa the code sheets, i.e.,  data were punched directly from
the code sheet.  At the  computer center printed listings of
each site were made and checked against a sample of original
data forms.  For  listing  the  data  on  magnetic tape, the
punched cards were sorted  by  site, family, and individual,
and a file en magnetic tape was created for each category of
data fora.

      A series of Fortran  IV  programs  were written at the
Cairo Dniversity Statistics Center for use on a Data General
•Nova1 computer.  These programs were for:

   1) preparing listings of various sub-sets of data.

   2) tasic tabulations of  important  variables  in the data
     set.  A number of  tabulations  were used to follow the
     work  in  the  central  laboratory,  and  were designed
     specifically to detect  errors and inconsistencies made
     by the laboratory workers.

  3) sequencing, matching, and renumbering of specimen data.

  4) validating and examining the consistency of coded data.

   5) eliminating duplicates in the specimen data.

   6) writing the data set onto magnetic tape  files.

      The complete  data  set  stored  on  magnetic tape was
transferred to the Dniversity of Michigan*s computing center
for continued analysis.  At  the  University of Michigan the
Michigan Terminal System  (HTS)  and the Michigan Interactive
Data Analysis Systea  (MIDAS) was used to:
                             98

-------
  1)  re-edit various sub-sets of  data  based on the results
     of verification programs run in Egypt,

  2)  Batch and nerge  the  data  from the family examination
     with the data from the speciaen forms and housing forms
     for the creation of a master data file.

  3)  to complete, following step number two, the descriptive
     analysis and  the  assessment  of relationships between
     variables in the data were coapleted.
                      Adjustment Scheme
      Since the sampling fraction  and  the age structure of
the saaple varied from study site to study site, an estimate
of prevalence  aade  by  simply  adding  together  all those
infected and dividing by the total number sampled in a given
area, for example in  Kafr  El  Sheikh, would be incorrectly
weighted.  To adjust  for  this,  a procedure *as formulated
using a  series  of  MIDAS  commands.    An  estimated number
infected was calculated for each age-sex group for each site
in a given area  of  study.  The age-sex specific prevalence
at  each  site  was  used  to  make  these  estimates.   The
estimated numbers infected in  each  age group for each site
were added together  and  divided  by  the  sum total of the
population of all villages studied in the area.  This result
was the adjusted  age-specific  prevalence.   The sum of all
these  estisated  to  be   infected  divided  by  the  total
population from all  sites  equalled  the  over all adjusted
prevalence  for   a   given   area.   Sex-specific  adjusted
prevalences were calculated  using  the  same procedure, but
selecting only male or female cases.
                             99

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                         CHAPTER IV
                           RESULTS
      The  results  have   been   divided   into  two  major
subheadings.  Under the first  subheading  is the results of
the study conducted in the  rural downstream villages in the
governoratcs of Aswan, Beni suef, and Kafr El Sheikh.  Onder
the second subheading is the  results of the study conducted
in the resettled Nubian villages of Kom Ombo.
                       2£ the Downstream S_tjjdj[


            Selection of the Sample and Besponse
      The study sites  or  villages  where  survey data were
collected were given the code  nuaber assigned to the health
unit  or  center  which  serviced  the  village  or villages
sampled.  Summarized in Table  27  are  the code numbers for
each village  or  site  and  the  naae  of the corresponding
health unit or  center  and  by  site  the number of persons
examined, the number  of  families  examined,  the number of
persons not giving a  urine  specimen, the number of persons
selected but not  attending (the so-called non-respondents),
the number of houses  examined,  and  the population at each
saapled site.  The  probability  of  being selected from the
total population sanpled was  0.181.   The population of all
villages  sampled  in  the  Downstream  Study  sites totaled
66,768 persons.  The  total  number  of  persons sampled was
12,059.  The probability of  being selected was not constant
from site tc site, ranging  from  0.08 to 0.58.  Because the
selection probability varied, grouped estimates of all sites
for a given area reguired the appropriate weighting based on
the saapling fractions.  Of  those selected, 93.2% attended.
Of the persons who   attended  the examination, 6.0% did not
give a specimen.  (11,555  specimens  in all were examined.)
The variation  in  response  between  study  sites was quite
marked, particularly in the villages sampled by health units
numbered H and  11.   If  these  two  sites are excluded the
response rate is increased to 96.75?.  There were 3020 houses
for which data  were  obtained,  although only 2894 families
attended  the  examination.    Apparently,  there  were  126
families who allowed  their  homes  to  be  examined and had
                             100

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intended to come to  the  examination  but were unable to do
so.   In  many  of   the  village  sites  everyone  selected
participated.  The very good response obtained in this study
is a remarkable  testiaony  of  cooperation by these village
people.


             Age-Sex Distribution of the Sample
      The number of persons  by  area selected and attending
the examination at the health  units  or centers is shown in
Table 28 by 5  year  age  groups,  except  for the first age
group which shows the number  of  infants less than one year
of age, and  the  last  age  group  which combines all those
persons 65 years or older.   Tables  29 through 31, show the
number of persons  by  age,  sex,  and  study site and their
respective distributions.  Generally there was little marked
difference between the proportional  size in like age groups
within   given area studied, i.e., for a given area the age-
sex structure was very  similar  from site to site.  Figures
15 through 17 show  the  distribution  of the age structures
between  sites  for   each   area  studied  and  graphically
demonstrate these  similarities.   However,  the  chi square
test indicated that the differences in age structure between
sites in  all  three  areas  were  statistically significant
(p<0.01) indicating  that  adjustment  for  age structure is
necessary when estiaating various  parameters within a given
area or between  areas.   Sex  ratios were not statistically
significant between sites, but  were significant between the
three different study areas (chi square, p<0.01).

      Figures  18  through  20  were  prepared  to  show the
relationship between the  sample  age  structure and the age
structure based on the  1960   (CAPMAS, 1960)  census for each
of the respective rural areas.  The resemblances between the
age curves of the  sample  to  the census age structure show
that as far as  population  structure is concerned the study
sites are representative of  the  areas from which they were
selected.
  Overall Prevalence of Schistosoaiasis in the Study Areas


                       Kafr El Sheikh
      The number of persons  in  the sample from all village
sites in the Kafr El Sheikh area positive for S.. hae§atobiua
was 1,257 or 28.5% of  the  sample,  and for S_. mansgni, 86T
persons or 19.65?.  There  were  336  persons (7.7%)  who were
positive for cva in the stool  or urine for both species and
1,782  persons   (40.3S)   who   were  infected  with  either

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    15. ••
fe  10.
     5.
      0.
                           ABE CYEARSD
Figure 15.  The age distribution by study site in the Kafr El
Sheikh study area.   Each line represents a study site.  The zero
on the abcissa represents infants less than one year old.   The
next point represents the age group 1 to 4;  the next, 5 to 9,
10 to 14, and continues in five-year age groups.
                              103

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                          Table 28
       The Number of Persons Attending the Downstream
                   Study by Age and Area,
    Age
   Group
    1-4
   13-14
   15-19
   20-24
   25-29
   30-34
   35-39
   40-44
   45-49
   50-54
   55-59
   60-64
   65 +
                               Study Area
Kafr El sheikh
Beni Suef
       66
      518
      724
      521
      284
      344
      214
      294
      237
      275
      146
      140
      115
       88
Aswan
103
442
510
365
211
215
207
214
207
144
178
87
114
111
42
206
550
385
245
211
184
227
225
179
197
96
109
91
   Total
     4651
  3677
3731
§.; fe§§S§i2^iSI or Si  ja.B§£Si  or both.  Those infected with
either one cr both species of schistosome comprise the group
of   infected   termed   "schistosomiasis".    The   overall
uncorrected prevalence of scfaistoscttiasis  in the Nile Delta
study area is 40.3%.  These  figures  are given in Table 32.
The percent positive in the  sample  from all sites for this
area does not correspond  to  an  estimate of prevalence for
all sites  because  of  differences  in population structure
between the study villages  and  because of the variation in
the probability of selection between sites.  Adjustments for
bcth age and sampling  fraction  were  made according to the
techniques described in Materials and Methods.  Briefly, the
appropriate weights were given  to  each age group according
tc the age structure  and  sampling  probability for a given
parameter measured by the  study  and  then added across age
groups for each site,

      The adjusted estimates or  prevalence  for the Kafr El
Sheikh area and the  standard  error   (a measure of sampling
precision) are also  given  in  Table  32.   The estimate of
prevalence   and   standard   error   for   S,_  ]v§effia_tobi u m,
Sji  JLafisofii i  f°r  infections  with  both  species  and  for
infections with either or both species by each study site is
shown in Table 33.  S..  sansoni was lower in prevalence than
                             104

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                          Table 29
              The Umber of Persons Examined in
               Kafr El Sheikh by Age and Site.
       ige
      Group
       5-9
      10-14
      15-19
      20-24
      25-29
      30-34
      35-39
      40-44
      45-49
      50-54
      55-59
      60-64
      65 +
16
                        Study Site Code Number
17
18
19
 20
6
77
128
117
128
90
76
35
68
42
69
23
2S
12
16
8
102
154
166
117
43
60
59
46
57
41
39
29
39
24
8
101
115
156
97
59
71
34
60
48
53
30
28
19
17
15
98
115
130
88
52
63
30
35
45
59
31
31
22
23
29
140
173
155
91
40
74
56
85
45
53
23
23
23
8
      Total
916
984
896
837
1018
±L± haematgbiujj at all  study  sites  except 19.  There was a
very high correlation  (r=0.967)   between  the prevalence of
the two species by site indicating that if the prevalence of
one organisa was high the  other would also be elevated.  It
follows that, if the conditions  for transmission for one of
the species was good  it  is  probable that transmission for
the other was also good for a given area.  The prevalence of
schistosoniasis was  quite  varied  from  site  to  site and
statistically significant (chi  square,  p<0.01), being more
than twice as high in  El  Aarzine  (16)  as in Mahalet Mousa
(19).  The differences ia prevalence between sites were more
marked for ^. haematobium than for S.. aansoni.

      It should  be  borne  in  asind  that  these prevalence
figures and  the  ones  to  follow  are  based  on  a single
examination of urine  or  stool.    Farooq and Nielsen (1966)
showed that  successive  examinations  increased  the number
found positive, and Heir,  et  al^ (1952) using rectal snips
indicated that the technique, examination of the excreta for
characteristic  schistosoae  ova,  was  very  insensitive in
respect  to  false  negatives.     Data  are  not  available
concerning the  quantitative  relationship between different
levels of prevalence  and  false  negatives.  It suffices to
                             105

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     the Beni
The Number
Suef Study
 Table 30
of Persons Examined in
Area by Age and by Study
               Site.

Age
Group
0<1
1-4
5-9
10-11
15-19
20-24
25-29
30-34
35-39
40-44
45-49
50-54
55-59
60-64
65 +
Study Site Code Number
11
9
55
47
59
43
23
24
18
23
26
16
14
7
13
7
12
29
21
133
123
61
54
50
57
48
43
27
31
21
19
29
13
26
99
153
145
108
47
57
44
57
46
38
31
22
20
27
14
26
91
130
85
63
30
46
48
45
32
30
41
25
27
32
15
13
76
106
98
90
57
38
40
41
60
33
61
12
35
16
      Total
   384
 846
920
751
776
say  that  meaningful  comparisons  can  be  made  only when
methodologies ate sinilar.  No  attempt was made during this
study  to  determine  the   proportion  of  cases  remaining
negative after successive  examinations.  Therefore, to most
accurately show relative  changes in prevalence, comparisons
require that the  separate  data  sets  are not adjusted for
false negatives.  It would be invalid to evaluate changes in
prevalence figures between different  studies which had used
different methods for detection  and estimation.  So long as
the same  sampling,  examination,  and estimation techniques
are adhered to, meaningful comparisons can be made.
                          Beni Suef
      la the five study sites  in the Beni Suef governorate,
3391  specimens  were  examined  for  schistosome  ova.  The
number  of  persons  positive   in   this  sample  was  951.
Prevalence between  study  sites  varied  significantly (chi
square, p<0.01) with a high of 37.3% positive in Naiim (13),
and a low of  16.9%  in  Shrief Pasha (12).   Standard errors
were calculated  for  the  prevalence  of schistosomiasis at
                             106

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                          Table 31
         The Nunber of Persons Examined in the Aswan
                   Area by Age and by Site
_ ^^^ -r -^^ - ^ r T -^ _ _
Age
Group
0<1
1-4
5-9
10-14
15-19
20-24
25-29
30-3JI
35-39
40-44
45-49
50-54
55-59
60-64
65 *
Study Site Code Number
1
27
104
158
133
93
40
50
52
54
59
42
43
22
19
12
2
11
92
118
150
125
92
62
37
68
57
51
50
24
30
26
3
2
80
76
60
52
47
27
30
23
22
22
30
14
14
9
4
0
84
143
137
58
29
41
28
47
51
46
44
16
36
35
10
2
46
90
70
56
37
31
37
35
36
18
30
20
70
9
      Total
908
993
508
785
537
each site  and  are  shown  in  Table  34.   Because the age
structure and sample  fraction  differed  froa site to site,
the overall prevalence for all  sites  in the Beni Suef area
was adjusted in the  same  fashion  as described for Kafr El
Sheikh.  The overall adjusted prevalence for schistosomiasis
was 26,1%.  The adjusted  prevalence  was  a few points less
than  the  unadjusted   crude   prevalence  of  28.1f.   The
prevalence of  schistosomiasis in  the  Kafr El Sheikh study
sites was more than one and  a half titaes higher, even after
adjusting for differences in  age-sex structures between the
two populations, than that of the Beni Suef study sites—and
this is highly  significant.   Although the differences were
not as great,  the  adjusted  prevalence  for .£._ haeiatobiua
alone in the Kafr El  Sheikh  sites  was also higher than in
Beni Suef and significant (chi square, p<0.301).  There were
20 persons in the sample  positive  for S._ man^onj. ova, less
than one percent of the saaple.   It is not known whether or
not these  persons  had  made  previous  visits  in the Nile
Delta.  It should  be  noted  that  63%  of these cases were
clustered in one village (Barout), and one case was detected
in a one year old infant.
                             107

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    20. T
tu

Q_


V)

U-
o
UJ
u
cc
UJ
Q_
                           AGE CYEARS1
Figure 16.  The age distribution by study  site  in  the  Beni  Suef

study area.  Each line represents a study  site.
                              108

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                          Table 32
          The Overall Prevalence of Schistosomiasis
              in the Kafr El Sheikh Study Area.
      Type of
     Infection
Number of Number of           Percent
Specimens Specimens Percent   Positive
Examined  Positive  Positive Adjusted*
 £_. mansoni

 Eoth Species

 Either One or Both
4404
4402
4386
4421
1257 28.5 30. 04+0.78
861 19.6 20.0+0. 32
336 7.7 8.0+0.20
1782 40.3 42.1+0.39
       *Adjusted for sampling fraction and age structure
  between study sites.  The figures following the plus and
  minus sign are the standard errors.
                            Aswan
      In  the   five   selected   sites   within  the  Aswan
governorate, 3728  specimens  were  examined for schistosome
ova;  180 were positive  for  S..  haematobijum or 4.8% of the
sample.   Variation in  prevalence of schistosomiasis between
sites was significant (chi  square,  p<0.01),  with a low of
0.2* in Guzaiera (2) ; and  highest in Bimban {10), which was
7.8X.  Standard errors and adjustments for age structure and
sampling fraction were calculated  using the same methods as
described in the  two  other  study  areas.   Table 35 shows
these results.

      In  Biraban  (10) ,  a  subsample  of  40  families  was
selected and examined.  This subsample was initiated because
of observed deficiencies in  the laboratory personnel.  This
was the only  site  where  incorrect procedure was observed.
Bimban  (10), ty virtue of  its  location on the west bank of
the Nile Fiver, is  considerably more isolated than villages
located on the east side of the river.  Villages on the east
bank can be easily accessed by the Aswan-Cairo Motorway  (see
map, Figure 11).  To reach  Bimban (10), the Nile River must
first be crossed in the  Nile sailing vessel, the "Falucca",
which is  the  only  available  means  in  this locale.  The
Bimban  (10) Health Center is another 4.5 kilometers from the
docking area on the west bank, and is reached either by foot
or by  donkey.   The  health  center's  ambulance,  the only
                            109

-------
      20. T
  1U
  B
  5
  0.
                             AGE CYEARS3
Figure 17.  The age distribution by study site in the Aswan study
area.  Each line represents a study site.
                              110

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                          Table 34
        Prevalence of Sr.  haematobiua in the Beni Suef
              Study Sites, Upper-Middle Egypt.
      Study
       Site
       Name
   Barout

   Shrief Pasha

   Haiim

   Beni Adi

   Ashmant

Study
Site
Code
11
!3 12
13
14
15
Number
Examined
325
710
857
708
758
S. haematobium
X Positive
27.5
16.9
37. 3
29.4
27.4
                                3418         26.7±0.25*
       * adjusted for sampling fraction and age structure,
       Standard error follows the plus and minus sign.
motorized  vehicle  in   the   village,   was  under  repair
throughout the period of  the survey.  The personnel staffed
at the Biaban (10)  Health  Center invariably resided either
in Daraw or in Kom Ombo  on  the  east side of the river and
commuted daily.    Because  of  these  and  other undesirable
working conditions, absenteeism  was  high,  and there was a
continuous turnover in the  staff  of the health center.  It
suffices  to  say   that  communication  and  administrative
control  were  hampered.    A   number  of  approaches  were
suggested to help improve  the  collection of data at Bimban
(10),  One likely alternative  way  was to permanently house
the necessary staff  in  facilities  available at the health
center.  This  suggestion  was  not  approved  by  the Aswan
Director-General  of  Health,  who  feared  that,  "once one
becomes comfortable in the  bath,  it  may be undesirable to
leave".  Although the rationale  behind this analogy was not
clear, it  was  not  pursued.   Since  there  had  also been
numerous coiplaints by  the  staff  about cooperation of the
selected villagers, it was decided that a subsample would be
drawn of 40 families or  about  100 or more individuals, and
that the physician at the  health center would carry out all
laboratory  examinations  of   the   urine  specimens.   The
subsample was drawn by  selecting  every 5th family from the
original  selected  sample   of  fanilies.   The  subsample,
therefore, was not independently selected.  Therefore, those
selected  in  the  subsample  were  examined  twice.   It is
                             112

-------
    20. T
Ul
0.
E
V)
u_
o
IU
o
                           AGE CYEARSJ
Figure 18.  The adjusted age distribution from the Kafr El Sheikh
study area and compared to the age distribution for  this same rural
area according to the 1960 census data  (CAPNIAS, 1960).  The solid
line represents the data from CAPMAS  (1960), the dashed line, from
the sample.
                                113

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                          Table 35
           Overall Prevalence of S_, haeaatgbiugi in
          the Study Sites of the Aswan Governorate.
      Study    Study                           adjusted
      Site     Site   Suaber  Percent Postive   Overall
      Name     Code  Examined S, haematobiuai  Prevalence*
Kazan Sharg
Guzaira
Abu Rish
Ga'afra
Biratan
1
2
3
4
10
984
947
474
760
663
6.9±0.9 4.1±0.2
0.2+0.1
4.2±Q,9
5.9±0.9
7.8±0.4
   Totals
3728
4.8±0.4
        *Calculated on study sites 1 to 4 only.  The
   figures following the plus and minus sign age the
   standard errors.
unlikely that new infections were acquired by individuals in
the subsaiple in  the  tiae  period  between their first and
second exaoinations but  this  possibility  jaust be borne in
mind.  It  is  especially  unlikely  in  light  of the large
increase  in  the  number   of  positives  detected  on  re-
exanination, and this confiras  the observation that correct
laboratory techniques  had  not  been  adhered  to.  Thirty-
seven, or 24.8%  of  the  subsample  were found positive for
schistosoaiasis.  These  findings  are  given  in  Table 36.
Prevalence was found to  be  over  six times higher than the
adjusted prevalence foe the  other four study sites combined
in the Aswan study area, which was 4.1%.

      In the overall saople  from  all areas and sites, more
persons were infected with schistosomiasis in the Nile Delta
than in any given study site  or sites south of the delta in
Beni Suef  or  in  Aswan.   In  turn,  the  overall adjusted
estimate of the prevalence was much higher in Beni Suef than
in any of the study sites sampled in Aswan.


 Age-Sex Distribution of Schistosoaiasis in the Study Areas
                             114

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                          Table 36
         Besults of the Subsample  in  Biraban,  Aswan,
            Parameter                        Result
        Number selected                           149

        Nunter examined                           149

        Number positive                            37
        for Sj,. haejBatofcj.ua

        Percent Positive                    24.8±3.5%

        Sampling Fraction                     0.04584
                       Kafr El Sheikh
      Tabulation of  the  number  examined  and   the  percent
positive in  the  entire  sample  from  this   area, for  both
species, and for either one or both infections by 5 year age
groups and by  sex  are  given  in  Table 37,  This analysis
shows that the age group  with the highest  proportion  of the
sample infected with  schistosomiasis,  i.e.,  either  one or
both infections, was in the  15-19 year olds.  This was  true
for both sexes with the males bearing a significantly  higher
proportion of the  infection.   Figure  21  shows  the  age-sex
prevalence distribution  of  schistosomiasis   for all sites
after adjusting for sample  fraction  and differences  in age
structure between sites.

      The age distribution  of  S±  lk§§iatobium infection in
the sample and for the adjusted figures was significant  (chi
square, p<0.01) showing a rapid increase in the early  years,
peaking in the adolescent  years  and dropping by adulthood,
in  the  early  20's.    This   is   a  typical   feature  of
schistosomiasis infections and can be  seen in Figures 21 to
24 which show the adjusted  distributions by  age  and  sex for
schistosomiasis, S.. ]!§.ejiatobiuja,  JA  Jia,nsojii, and infection
with  both  species,   respectively.   The  distribution  of
prevalence by age  for  S^  Jl§..SJ>orii   (Figure   23)  was  not as
marked as for _£_.  I»aeja_tobi_um  and  has  an atypical  rise in
prevalence in the older  age  groups.  This was more  evident
in the males than  in  the  females.   Farooq, et ajU  (1966)
comments on the differences in the age distributions  between
•2.1 bl§53tobiuB and £_. jsa.nsj3.ni and notes that  S. mansoni  does
not  fall  as  sharply  in  the  adult  age  groups   as  does
                             115

-------
      20. T
  UJ
  u.
  o
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   f£
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   0.
                             ASE CYEARS3
Figure 19.  The adjusted age distribution from the Beni Suef study
area compared to census data for this area (CAPMAS, 1960).  The solid
line is the data from CAPMAS (1960), the dashed line, from the sample.
                                  116

-------
   UJ
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   u_
   o

   I
   o
   15
   a.
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Figure 20.  The adjusted age distribution from the Aswan study area
compared to census data this same region (CAPMAS, 1960).  The solid
line is the data from CAPMAS (1960), the dashed line, from the
sample.
                                 117

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.§_• liaejatjobijif.  5. jansoni seems  to be acquired slower and
to persist longer than  S.. haejjatobium infections.  The wide
spread between  the  age  prevalence  of schistosomiasis and
those  infected  with  both  species  (see  Figure  25) does
suggest separate transmission sites and supports this  view.
                          Beni Suef
      The number of persons  positive  for S._ haematobi-Uffl in
the Beni Suef area by  five  year  age  groups and by sex is
shown in Table 38.  As in the Kafr El Sheikh sites the  15-19
age group had  proportionately  the highest prevalence.  The
nunber of females infected was less than the nales for  every
age group.  Age and  sex distributions were significant  (chi
square, p<0.01) for both adjusted and un-adjusted figures in
the Beni  Suef  area.   Proportionately  fewer  females  were
infected in Beni Suef  than  in  the  Kafr El Sheikh sample.
The prevalence was 2.08  times  greater  in the males in the
Beni Stief sites than in  the females, whereas the prevalence
was only  1.4  tiaes  higher  in  males  in  Kafr El Sheikh.
Figure 26 shows  the  age-sex  prevalence  (after adjustment)
for S. haeaatobiun in Beni Suef.
                            Aswan
      The   age-sex    adjusted    prevalence   curves    for
•Li ^§§13*5ilJIS have been prepared  in the same manner as  for
the results from Kafr El Sheikh  and Beni Suef and are shown
in Table 39 and  Figure  27.   Bimban   (10) was not included
with these results,  but  was  treated  separately because  it
was not  a  desert  type  village.   Results  of the age-sex
prevalence tabulations for the sample and the subsample from
Biaban are given in  Table  40.   Eiraban  (10)  was originally
selected as a site that was  not typical of this region,  but
rather isolated and located in  an  area more similar to  the
condition of  other  villages  located  in  a flat irrigated
plaia.  The elevated  prevalence  of  schistosoaiasis in  the
sabsaaple from this study site indicates that the conditions
for transaission were strikingly different from those at  the
other four  study  sites,  all  of  which  had uniformly  low
prevalence.

      Schistosoaiasis prevalence was  highest (13.3%)  in  the
age group 10 to 14 years  old for these study sites numbered
1 to 1 grouped together.  This is one age group younger than
the age group  of  highest  prevalence  in  the two northern
areas of Kafr El  Sheikh  and  Beni Suef.  Prevalence in  the
aales was over  4  times  higher  than  in  the females.   In
Biaban (10) , the age prevalence was slightly erratic, with a
high variance most  likely  due  to  the  small  size of  the
                             119

-------
                          Table  38
           Age-Sex Distribution  of  S^ haenatobiua
      Infection  in the Sample  from  the Beni  Suef Area.
                   Infected  with  S. haematobium
    Age        Males
   Group  	
                 Females
                          Total
          f Examined  %    f  Examined   %
                             #  Examined
<1
-4
-9
-14
-19
-24
-29
i-34
.-39
-44
i-49
i-54
'-59
I-64
i5 +
20
158
312
265
200
71
96
85
102
92
68
77
50
61
69
0.0
5.1
30.8
59.7
69.0
50.7
38.5
32.4
39.2
38.0
19.1
23.4
32.0
29.5
14.5
21
137
249
237
155
121
113
120
108
108
75
97
34
53
39
0.0
5.1
14.5
38.8
37.0
22.3
10.6
14.2
11.1
8.3
9,3
14.4
8,8
11.3
5.1
41
295
561
502
355
192
209
205
210
200
143
174
84
114
108
0.0
5. 1
23.7
49.6
55,2
32.8
23.4
22.0
24.8
22.0
14.0
18.4
22.6
21. 1
11.1
   Totals
1726
37.7
1667
18.1
3393
28.1
population in the sutsaaple.   Males had more schistosomiasis
than females, but the ratio was similar to that in the study
sites of Beni Suef:   2.6.
     Environmental Aspects of the Downstream Study Sites
                       Kafr El Sheikh
      In the past the villages in Kafr El Sheikh governorate
had obtained their  domestic  water  supply  from the nearby
canals  and  drains,   or,   where  available,  from  public
standpipes supplied by deep  wells.  (A standpipe is defined
as a public water outlet of  one  or more taps attached to a
vertical water pipe  that  may  or  may  not have additional
support, but typically are  attached  to a vertical concrete
slab.)  Since 1958, the  standpipes  have been supplied by a
water treatment plant at  Fowa.   This is a typical tertiary
water treatment plant; however, pressure in the distribution
                             120

-------
                          Table 39
        The number Examined and the Percent Positive
              by Age and Sex for S_. haematobium
            in the Aswan Study Area Excluding the
                  Results from Bimlan  (10).
                   Infected with S_. haeraatobjuin
     Age
    Group —
  Hales
       Females
                 Total
          I Examined  %   f Examined  %  I Examined  %
    1-4
    5-9
    10-1i»
    15-19
    20-24
    25-29
    30-34
    35-39
    40-44
    45-49
    50-54
    55-59
    60-64
    65 +
    NS*
13
156
235
255
156
78
55
47
61
78
68
75
45
46
43
12
0.0
0.0
7.7
20.8
12.2
5.1
1.8
2.1
0.0
1.3
1.5
1.3
0.0
0.0
0.0
8,3
                  17
                 170
                 245
                 218
                 162
                 123
                 116
                  93
                 123
                 101
                  82
                 8.3
                  28
                  38
                  38
                   5
0,0
2.9
2.0
5.0
1.9
0.0
0.9
1. 1
0.8
1.0
0.0
0.0
0.0
0.0
0.0
0.0
30
325
480
473
318
201
171
140
184
129
150
158
73
84
81
17
0.0
1.5
4,8
13.5
6.9
2.0
1.2
1.4
0.5
1. 1
0.7
0.6
0.0
0.0
0.0
5.9
    Total
1423
7.0
1642
1.7
3065
4.2
          * Not Stated.
system is not always continuous,  due to demand.  The number
of standpipes  by  study  site,  the  number  of persons per
standpipe, and the  prevalence  of  schistosomiasis by study
site is shown in  Table  41.   There  seems to  be no obvious
relationship  between  schistosomiasis  prevalence  and  the
number of persons per  standpipe,  which  ranges from 540 to
2C7.  Table 42 shows the number  of persons in  the sample by
source of water and by  the  type  of use.  Since the use of
different water sources is not exclusive, the numbers show a
measure of preference by the  persons  in the sample.  It is
evident  that  outside  pipes   (standpipes)   were  the  most
commonly used source of drinking  water, but the other water
use activities,  such  as  bathing,  were frequently divided
between the protected sources and the canals or drains,
      An  analysis  to
           determine
                121
             the  relationship between

-------
      80. T
   u
   2
   UJ
   a:
   a.
   UJ
   o
          0.
10.    20.    30.    40.
60.   +
                             AGE CYEARS3
Figure 21.  The adjusted age-sex prevalence distribution for

schistosomiasis for all study sites combined in the Kafr El Sheikh

study area. The long dash corresponds to males, the short dash to

females,  and the solid line  for the total.
                                122

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                          Table 40
 The Nuaber Exaiined and the Percent Positive by Age and Sex
                                Biniban (10) Sufcsample.
                   Infected with S. haematobiun
      Age      Males
     Group 	
              Females
                      Total
           I Examined  %  f Examined %  * Examined  %
0<1
1-4
5-9
10-14
15-19
20-24
25-29
30-34
35-39
40-44
45-49
50-54
55-59
60-64
65 +
0
2
7
12
12
10
5
3
1
7
2
4
3
2
3
     Total
73
0
0
86
50
33
60
20
100
0
0
0
0
0
0
0
1
5
11
12
10
3
3
a
6
6
2
4
1
3
1
36
76
0
0
33
11
10
33
0
20
17
0
0
0
0
0
0
1
7
18
24
22
13
8
11
7
13
4
8
4
5
4
0,0
0,0
55,6
29.2
31.8
53,8
12.5
36. 4
1,4.3
o. a
0.0
0.0
0.0
o.a
0.0
14
149
24.8
schistosoae infection and the  source  of water did not show
any distinctive pattens until all  those who had scored the
data forms for aore than  one  source were eliminated in the
piped inside  and  piped  outside  categories, the rationale
being  that  if  an   individual   obtained  water  from  an
unprotected source  as  well  as  a  protected  one it would
confound the  impact  on  the  evaluation  of  the protected
supplies.  The results shown in  Table  43 by source and use
of water are contained data  for  all  study sites in Kafr El
Sheikh.  These persons fortunate  enough to have water piped
into their hones and who did not supplement this supply with
sources froa  outside  the  home  had  lower prevalence than
those  who  obtained   their   drinking  water  solely  from
standpipes.   The  latter  group,   in  turn,  had  a  lower
prevalence than those who used the canals as a source.  This
observation was consistent regardless  of what the water was
used  for  and  showed  an  even  greater  differential  for
JLt rcansoni infections, which is given in Table 44.

      In the Kafr El  Sheikh  study,  90%  of the sample had
latrines.    Prevalence   of    either   species   was   not
significantly different between  those  having  a latrine or
                             123

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                          Table 41
          The Prevalence of Schistosomiasis and the
        Distribution of Persons per Standpipe  in the
                 Kafr El Sheikh study area.

Study
Site
Code
16
17
18
19
20

f Standpipes
20
7
4
5
28

Persons per
Standpipe
207
420
508
540
262

Schistosomiasis
Percent
Prevalence
66.5
45.9
31.2
21.5
28.7
                          Table 42
             The Number of Persons in the Sample
                     from Kafr El Sheikh
                  by Hater Source and Use.
                                  Water Use
  Water Source
                  Drinking Bathing Laundry Utensils Animals
Piped inside 197 193 105
Piped outside 4183 3631 2909
Hand pump inside 12 57 57
Hand pump outside 8 10 10
Canal 909 3091 2993
85 29
2878 121
57 2
2 0
2927 2822
not having one.
                            124

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      SO.i
      60.
   UJ
   u
   §
   UJ
   I
       40.-
       20.-
        0.
          0.
10.    20.    30.     40.    50.    60.   +
                             AGE CYEARSD
Figure 22.  The adjusted age-sex prevalence distribution for S_.
haematobium infections for all  study  sites in the Kafr El SheBdi
study area. The  long  dash corresponds to males, the short  to
females,  and the  solid line for the total.
                              125

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                          Table 43
 The Percent Prevalence of _§_._ taemajtobi^im by Source and Dse
       of Water Supply from Kafr El~Sheikh study area.
                                Hater Use
  Sater Source  —
                Drinking Bathing Laundry Uteasils Animals
Piped inside
Piped outside
Canal
13.3
19.2
33.3
13.3
20.0
32,8
13.3
18.2
34.6
13.3
18.0
34.6
0.0
16.7
32.9
                          Beni Suef
      fable 45 shows the  distribution  of standpipes in the
study sites  of  Beni  Suef.   Again,  no relationship seems
evident between the suaber of  persons using a standpipe and
schistosomiasis prevalence,  The  number  of  persons in the
sample and their respective sources of water by use is given
in Table 46.   Hand  pumps,  often  seen  installed near the
canals, are a CCIBHIOE  source  of  water  in this area.  When
water source  data  and  prevalence  of schistosomiasis were
adjusted for multiscurce uses a distinctive pattern emerged,
similar to that seen at the  Kafr El Sheikh sites  (see Table
47).    Prevalence   of   schistosomiasis   decreased   with
improvement in the guality of water source.

      Only 37.35! of the houses  in  the sample from the Beni
Suef area had latrines.  The  persons residing in homes that
had latrines had less schistosoaiasis, 22.6%, than those who
did not, 31.4%,
                            Aswan
      There seems to  be  a  consistent lack of relationship
between  the  number  of   persons  per  standpipe  and  the
prevalence of schistosomiasis.  Data from the study sites  in
Aswan,  and  tabulations  for  the  number  of  persons  per
standpipe  (given in Table  48)  are  in accordance with this
observation.  In  the study  sample  from  sites 2, 3, and 4
(Guzaria, Abu Eish, and Ga'afra, respectively) water sources
for domestic use  were  obtained invariably from standpipes.
Only small irrigation  canals  are  found  in the area where
                             126

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       80. T
   tu
   u

   UJ
   _l


   tu
       60.-
       40."
   B
   a:
                              AGE CYEARSD
Figure 23.  The adjusted age-sex prevalence distribution for S.

mansoni infections for all study sites in the Kafr El Sheikh study

area.  The long dash corresponds to males,  the short dash to females,

and the soled line -for the total.
                                 127

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                          Table 1414
   The Percent Prevalence of S_. majsoni by Source and Use
     of Water Supply iu the Sample from Kafr El Sheikh,
                                Hater Use
  Rater Source  	
                Drinking Bathing Laundry Utensils Animals
Piped
Piped
Canal
inside
outside

6.
12.
24.
7
3
7
6,
12.
21.
7
8
4
6.
11.
22.
7
9
1
                                            6.7     ND*

                                           11.7      ND

                                           22.0    21.2
        * No Data
                          Table 45
  The Prevalence of Schistosomiasis and the Distribution of
     Persons per Standpipe in the Eeni Suef Study Area.

Study
Site
Code
11
12
13
14
15

Number of
Standpipes
0
6
8
7
13

Persons per
Standpipe
0
827
201
968
712

Percent
Prevalence
27.5
16.9
37.3
29. 4
27.4
these  villages  are   located,   and  are  at  inconvenient
distances from the  villages,  thus  precluding their use in
favor of the standpipes.  In  Kazan  Sharg (1), the Nile was
the exclusive source of water.   It should be mentioned that
there are nc  upstream populations from Kazan Sharq (1); the
village is very near the outfall of the old Aswan Daa, where
the water quality of the River Nile in Egypt is at its best.
Approximately one month  following  the  field work in Kazan
Sharq (1)  standpipes  were  installed throughout the village
and supplied by the new  Aswan water treatment plant.  Bater
                             128

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                          Table 46
          The Number of Persons in the Sample from
             Beni Suef by Water Source and Use.
                                  Hater Use
  Water Source



Piped inside

Piped outside

Hand punp inside

Hand pump outside

Canal
Drinking Bathing Laundry Utensils Anisals
11
306
ide 46
side 583
30
9
301
42
561
65
9
200
41
439
272
9
181
40
435
242
0
2
0
26
296
                          Table 47
          The Percent Prevalence of _£_. faaegatobium
                 by Source and Use of Water
            supply in the sample from Beni Suef.
  Water Source
                                  later Use
                  Drinking Bathing Laundry Utensils Animals
Piped inside
Piped outside
Hand pump inside
Hand puap outside
Canal
10.5
21.4
27.7
30.6
35.3
9.7
21.0
30.0
31.0
35.2
15.4
19. 1
30.9
29.0
31.7
9.7
19.3
27.2
28. 5
31. 3
NC_
NC
NC
NC
32.3
      * No Cases.
for standpipes in Guzaria  (2) , and in Abu Rish  (3) , was also
supplied by the treatment  plants  in Aswan.  In Ga'afra, the
water for standfipes  was  supplied  by  the water treatment
plant in Dara* fsee nap,   Figure 11).  In Bimban  (10), 75. 4X
of the hoses had indoor  hand  pumps and 21.5% of the saiaple
                             129

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obtained their water from outdoor hand pumps.  The remaining
3.951 were scattered between  the  canals and the drains,  In
the subsample from Biaban (10), doaestic water was uniformly
obtained from hand pumps inside the house.

      The percentage of the  sample  with latrines are shown
in Table 19.  In the sample  as  a whole, 65.1% of the homes
had  latrines,  an  impressive  figure  for  a  rural under-
developed area, of which the study sites at Aswan are a good
example.  The relationship between schistosome infection and
the presence  of  a  latrine  was  significantly  lower (chi
square, p<0.01) for those who  had  them in study sites 1 to
4,  These results are also shown in Table 49.
                    of the Resettled NubLan


            Selection of the Sample and Response


      As mentioned, the villages selected for study were the
same villages surveyed by  Zawahry  (1961) before the Nubians
were relocated.  In addition,  data were also collected from
two other villages, Tuskha (6)  and Kalabsha  (9).  Summarized
in Table 50  is  the  descriptive  pattern  of selection and
response by study site.  All those selected and requested to
attend did so.  The  combined  population  of all the Nubian
sites examined was 16,065  and  the  total number of persons
examined was 3,275.   Probability  of  selection varied from
site to site as it  did  throughout the Downstream Study and
ranged fro» 0.10 to 0.69.  There were 193 who did not give a
urine specimen and 2,762 who did, or 85% of the total.


          Age-Sex Distribution of the Nubian Sample
      The age-sex distribution  of  the  Nubian  sample as  a
whole and by site is given in Table 51.  Figure 28 shows the
proportional age curves  by  site  for comparative purposes.
The age and  sex  structure  between sites was statistically
significant (chi square, p<0.01).   Typically, Nubia has had
more females than Bales as  is  the case in this sample, but
past  data  (Zawahry,   1961)  suggests  that  males  are  in
proportionately greater number than before.


  Overall Prevalence of S^ haematobium in the Nubian Sample


      The  Eunber   of   persons   in   the  sample  passing
S.s lil§Sill2J9i]iJl iQ their urine  or  stool was 214, or 8.9% of
the sample.  After adjusting  for  the sampling fraction and
                            130

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         80. T
         60.--
     UJ
     u
     UJ
     UJ
     £   40.
     UJ
     UJ
     Q_
                               AGE CYEARS]
Figure 24.  The adjusted age-sex prevalence distribution for infections
with both species for all study sites in the Kafr El Sheikh study
area. The long dash corresponds to males,  the short dash to females,
and the solid line for the total.
                                  131

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                          Table 48
                  The Number of Persons per
              Standpipe by Study Site in Aswan.
   Study
   Site  Number of  Population Persons per ^Prevalence of
   Code  Standpipes             Standpipe  S. haematobium

1
2
3
14
10
0
8
3
55
0
2371
4021
1915
4701
3076
0
503
638
85
0
6.9
0.2
4.2
5.9
22. 1
age-sex differences between the  five  study sites the over-
all  estimated  prevalence  was  1.2%.   The  prevalence  of
S_.  haematobium  at  each  site  varies  significantly   (chi
square, p<0.01), although generally low in the Nubian sample
as a whole,  except  for  Kalabsha  (9).   These results are
shown in  Table  52.   The  suprisingly  high  prevalence in
Kalabsha (9) seems to  be  atypical  of this region, and the
higher prevalence in  females  than  males  is unique to all
study sites throughout.  This  aspect is further assessed in
the following section.   Figure  29  shows  the age adjusted
prevalence in the Nubian  sample  for S_. haematgbiuffl.  These
results  do  not   exclude   the   possibility  of  sporadic
ILt JLSBJiP.Bi infections in any of the Upper Egypt study sites.
             Environmental Aspects of New Nubia
      The villages  of  New  Nubia,  built  in  1963  by the
Egyptian government in a  attempt to compensate these people
for the loss of  their  hones,  are typical of expedient low
cost  "social"  housing  projects  with  each  housing  unit
invariably constructed like  the  one before it.  Therefore,
environmental variation from village to village was minimal.
                             with  a latrine, and standpipes
                              villages.  Except for Kalabsha
                              site), all the villages of new
                            east of the Aswan-Cairo Motorway
All houses had  been  built
were present throughout  the
(9) and Daboud  (not a  study
Nubia were located to  the
at the  edge  of  the  Rom  Ombo  agricultural  plain in the
desert,  strategically  located  at   a  distance  from  the
irrigation water courses.  Treated  water  was supplied by a
joint  distribution  system  connected  to  both  the  water
                             132

-------









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-------
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20.    30.     40.    50.
                                               60.
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 Figure 25.  The adjusted age prevalence distribution for those infected

 with both species  (dash line) and for those infected with either
 or both species (solid line).
                                  134

-------



















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-------
    80.-,
                                                       \
        0.     10.    20.    30.    40.     50.    60.   +
                           AGE CYEARS3
Figure 26.  The adjusted age-sex prevalence  distribution for S_.
haematobium  infections in the study sites from the Beni Suef study
area.  The long dash corresponds  to males, the  short dash to females,
and the solid line for  the total.
                                136

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                          Table 51
        The Number Examined and the Percent Positive
   by Age and Sex for S± JL§§l§tabiuj£ in the Nubian Sample
                  Infected with S. haematobium
    Age       Males
   Group	
                 Females
                          Total
         I Examined  %   # Examined  %   # Examined  %
0<1
1-4
5-9
10-14
15-19
20-24
25-29
30-34
35-39
40-44
45-49
50-54
55-59
60-64
65 *
14
126
164
179
145
60
47
44
37
3
54
44
44
42
75
0.0
1.6
4.9
14.0
18.6
31.7
21.3
18.2
16.2
17.8
7.4
9.1
11.4
2.4
1.3
6
130
1b6
159
181
119
109
97
122
98
95
75
91
54
112
0.0
1.5
8.1
3.8
9.4
10.1
13.8
8.2
5.7
9.2
8.4
8.0
4.4
1.9
4.5
20
256
350
338
326
179
156
141
159
143
149
119
135
96
182
0.0
1.6
6.6
9.7
13.5
17.3
16.0
11.3
8.2
11.9
8.1
8.4
6.7
2.1
3.2
   Total
1120
11.4
1634
7.0
2754
8.9
treatment plants in Daraw and  in Kom Oabo.  Villages at the
extreme   end   of   this   distribution   system   suffered
intermittent  water   supply   due   to   excessive  demand,
especially in tbe  hot  dry  summer  months.   El Malki  (7),
Kurta (8), and Kalabsha  (9)  were  all limited to a few hours
a day when the water  pressure  in the system was sufficient
to reach these  villages.   All  villages  ia new Nubia have
electricity, a benefit of the AHD.
                             137

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     80. T
     60.-
 IU
 o
 UJ
 UJ
 UJ
 o
     40.-
     20.--
         0.     10.    20.    30.    40.    50.    60.   +
                            AGE CYEARS3
Figure 27.  The adjusted age-sex distribution for S_.  haematobium
infections in the study sites from Aswan study area.   The  results
from Bimban (10) are not included. The  long dash corresponds to
males, the short dash to females,  and the solid line  for the total.
                               138

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      20. T
          0.
                             AGE CYEARS3
Figure 28.  The age distribution by study site in the Nubian sample.
Each line represents a study site.  The abnormally high percentage
of persons in the sixty and over age groups was found in Kurta (8),
represented by the-, solid line.  It reflects the excessive outward
migration by younger groups.
                                139

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                        Table 52
        The Percent Prevalence of S_. hag a at obi urn
           in the Nubian Sample by Study Site
 Study
  Site
  Name
Ballana

Tuskha

El Halki

Kurta

Kalabsha
Study
Site
Code
  5

  6

  7

  8

  9
                         Infection with S. haematobiuat
 Number
Examined
      535

      649

      597

      461

      512
Percent
Positive
      5.8

      3.7

      2.0

      1.7

     32,8
Total
                  2754
                         8.8
                           140

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    80. T
    60.-
    40.--
                           ABE CYEARSD
Figure 29.   The  adjusted age prevalence distribution for S.  haematobium
infections  in the Nubian sample.                         ~
                                 141

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                          CHAPTER V
                 DISCUSSION AMD CONCLUSIONS
      Like the Results section,  the discussion is presented
under two major subheadings:  the  downstream and the Nubian
studies.
           21iS fiOMJi-streaB Stud^i  General Aspects


      A large scale country-wide  field survey was completed
in the rural areas  of  the  Nile Valley downstream froa the
AEE.  Thirty-three  villages  were  chosen  on  the basis of
typicality to represent the three  major regions of the Nile
Valley in Egypt:   the  Nile  Delta, Upper-Middle Egypt, and
Upper  Egypt.   In  these   village  sites  members  of  the
population were  selected  according  to known probabilities
and  examined   for   infection   with   schistosoaiasis  as
described.  Prevalence  figures  for  schistosomiasis in the
respective  areas  have  been  adjusted  for  differences in
sampling fraction and  age  structure  of the populations at
the various study  sites,   (Only  adjusted figures are used
when comparisons are made  between the different study areas
or between the results  of  this  research and other works.)
Data  were  also  obtained   on   the  housing  and  village
environments of the sampled population.

      The general aspects of the results of this survey show
that the prevalence  of  schistosomiasis  is  highest in the
rural villages sampled in the north central delta where both
species of schistosome  are  present.   Aside  from the long
term intensive perennial  irrigation  in  the delta which no
doubt has contributed  to  the  high overall prevalence, the
increased risk of acguiring either species is another reason
that the prevalence of  schistosomiasis is elevated.  If all
those who were  infected  with  one  species were invariably
infected with the other there  would  be only an increase in
morbidity rather than  in  prevalence.  However, the results
show  that  infection  with   either   or  both  species  of
schistosome is over five times more prevalent than infection
with both  species.   This  large  difference  in prevalence
shows that transmission of the two species is occurring to a
great degree at separate sites.
                             142

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      Faroog  (1966) has  also  observed  that  transmission  of
the two species depends on  separate  sites.   Main  drains  and
canals were found to  play  a  more   significant role  in.  the
transmission  of  S_,  hae g&tobi UJB ,  whereas   distributaries,
(smaller canals used to  distribute   the   water  to the field
channels)  were more important for J..  JS§Ssoni  transmission.

      The   pre?alence   of    both     infections    and    of
schistosomiasis  varied  dramatically    from   one  site   to
another^  reconfirming  that  schistosomiasis  in   Egypt   is
focally distributed.  Scott   (1937),  Faroog,  et al.. {1966),
and others have also noted  this  aspect.   This was also  true
for  the  study  sites  in  Benx  Suef   and   in  Aswan.   The
interesting   correlation   between     the    prevalence    of
S_* haejBatob_ium and S_. jansoni  by  site  in Kafr  El Sheikh  in
this  study,  suggesting   that   conditions   good  for   the
transmission of one  species  are  favorable   for  the  other,
have not been observed before.  It is not  known  whether  this
relationship is true  in  other   sectors   of   the  Nile Delta
where  prevalence  of  the  two   species   is   at   an overall
different  level  or  not.   It   is   possible  that  if  good
conditions for S± !§Bso_fii  transmission  exist then  they  are
also favorable for JBj,  k§.§S§.i;2feiJlSr   ^u1t n°t  vice  versa.   It
is significant that the  prevalence of  S._  jgaasonj.  infections
was  invariably   lower   than   jr.  Ji§§fiatobium   infections
rcgardlcsss of the  study  site  picked.    This is  consistent
with findings of past surveys in  the  Nile  Delta,

      The  age-sex  distribution   of    Sj,.  k^ematobium   was
typically higher in males  than   females   and  highest  in  the
younger age groups,  S,. ftansoni infections did not follow  as
closely the typical age-related distribution,  remaining  high
in the adults rather  than  dropping  ia prevalence  like  the
Si h.§§!§jkotiutt infections.  A number  of  hypotheses have  been
formulated to explain  the  age-related  differences  for  both
species (Faroog, et  al..  1966),  but  the  lack of  a  higher
prevalence in the adolescent  years   for S_. §ans;oni  reguires
further  explanation.   Two   possibilities   are   suggested.
First,  it  is  possible   that   the   age  distribution   of
JLi !§H§-Sfi! seen in the  study  sites  is  being  altered  due  to
spontaneous changes in the  ecology   of  the  disease and  its
transmission.   Evidence  is  now  available   to   show  that
changes in prevalence have been   occurring in  this area over
a rather long term as discussed in the  Review  of Literature.
Second,  locally  iipleiaeBted  control   programs   are  often
directed at the  groups  with  the highest prevalence, i.e.,
the youths  School  health  prograas  designed to  detect  and
treat the enrollees for  schistosoraiasis are  required  by  law
and are carried out fcith  varying degrees  of  efficiency.   It
is possible that these  and  other control measures  have  had
seme success, thus depressing the peak  of  prevalence usually
seen in these age groups.  However, the  age prevalence curve
f°r JU  klL§3§tobiuB  was  not  depressed   in   the   young  age
groupst  as  would  be  expected  if  control  measures  were
                             \ H~O

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working.  Studies in Beheira  by  Farooq and Hairston  (1966)
showed that  the  incidence  rates  for  £>•._ haematobium  were
almost  three  times  as  high  as  those  for  S^  §§.B.sonj..
although this explanation is  the  uore unlikely of the  two,
it is possible that  some  of  the S. haematobium infections
were cured but quickly reacquired.

      South of the Nile Delta in  the study sites selected  in
the   Beni   Suef   area,   the   adjusted   prevalence    of
S_s haejatobium was  a  few  points  below  that of the delta
sites in Kafr El  Sheikh,  26.1%  as compared to 30.0%,  The
age-sex prevalence followed a  typical distribution in these
study sites.  Hhen only sales are compared, the results  from
Beni Suef show,  interestingly  enough,  that  this area was
higher in prevalence.  The prevalence for males in Beni  Suef
is 37. OS and in  Kafr  El  Sheikli cnly 35.2%.  Obviously the
prevalence of S_. haejiatobiuj  in  females  was much lower  in
Beni Suef.  Indeed,  the  difference  in the distribution  of
j?.i haema^ofciuffl prevalence between  the sexes is much greater
in Beni Suef, almost twice that   in the delta sites.   In the
villages studied  in  Aswan,  the  differences in prevalence
between sexes were was  again  greater,  by two times.   This
sex related differential  seems   to  increase  from north  fco
south, as the  prevalence  of  the  disease decreases.   This
unique observation has  a  number of implications concerning
control strategies.

      In the  Aswan  study  sit*.'.-;,  except  for Bimban  (10),
prevalence  of  S±  haeraajiobium   wa3  remarkably  low.   The
overall adjusted prevalence was   only 4.1%.  As just pointed
out, the difference in prevalence  between the sexes was the
greatest  here  of  alA  the  study  areas,  and  there  was
significant variation  o£  prevalence  between  study  sites.
The prevalence of  _£_.  haematobiutt  in  Guzaiera  (2) was the
lowest recorded  (0.2%)  in  any   of  the downstream villages
studied.  Many of the  villagers  from the Guzaiera  (2)  site
were employed in occupations other than agriculture and  many
worked in the city of  Aswan  which is only a few kilometers
away to the south.  Equally  important, and typical of other
villages with low  prevalence  ii;  this study area, Guzaiera
(2) is located on  high,  dry,  barren ground outside  of the
narrow strip of cultivated  land  that  lies along the Nile.
Continuing north froa here, t.ho   Ni U» Valley is very narrow,
widening  gradually  a?  it  passes  through  the  next  two
governorates, Qena and Sohag  (sot..  raap, Figure  10).  Only  in
the Kom Omfco  plain  does  the  valloy  widen to any extent.
North  of  this  plain  the  valley  returns  to  the  narrow
confines  typical  of   the   region.   Land  available  for
cultivation  is  scarce  throughout  the  Aswan governorate,
except in Kcm Ombo, and  the local villagers have wisely not
built on land that could be  used for growing crops.   In the
study sites located north of the  city of Aswan and south  of
the Kom Orabc plain, the village!s live at a greater distance
from the irrigation canals than   do the villagers located  in
                              144

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the delta or  in  Upper-Middle   Egypt.    In   the delta or in
Upper-Middle Egypt villages are   built  in and are surrounded
by cropped lane).   In  addition   to   being isolated from the
irrigated land, many of the villages  of  the  Aswan region are
supplied with  treated  water,   as  was   pointed  out in the
      ViJlagrr;  ar^  found   within   the   cropped  areas with
increasing frequency as one  travels   north  out of Aswan into
the Qena and  Sohag  qover norates,    North   of  Sohag only a
ssrai? fnct- i^n of *';*"•  rur-i1.   p°Tu lat" i°n  resides ia villages
located outside the cultivated   land,  and these villages are
oft^n bounder! on one side by  their  fields.   For convenience,
"desert village" has  been   defined   as   one located on dry,
un vegetated , barren ground;  and   a  "non-desert village" is a
village in and surrounded  by  irrigated  productive land.  In
order to have some  measure   of   prevalence in an non-desert
•/ i 1 1 jyvr Bialrii' (10), on the   west   bank   of the Nile in the
KOB uabo plain, was  surveyed.   Sugarcane is cultivated here
and thick,  stands  of  date   palms   are   common.    Water for
dotsppti'-: purposes is either   piped   from  a  deep well, pumped
by h ntd  fioir  -h-ti. low  we Hi?,   or   * aken  directly from the
nearby canals.  fn this  village   24.3*   of a subsample were
positive for  S.  hagjBjit.o.biiiS'    Although  these results are
ba5» .1 on -j ID-'   limited  sample   than usual in this village
area,  it  is  a   strong  indication   that  schistosoiaiasis
prevalence i '~ '-ou?u der;ably higher   in  the non-desert type of
village.  This new evidence1  suggests that prevalence between
villages can vary greatly, certainly more than what has been
seen  in the northern areas of  Beni  Suef  and Kafr El Sheikh.
This  is aiost likely  true  of  Upper  Egypt in general where
both  these types oE  villages  are   common.  It is important
that  future  prevalence  surveys   in  Upper  Egypt take into
consideration the  types  of   villages  selected  for study.
Differences in water suppjy   o±  selected  villages (discussed
below)  and di f f ei enoes in jocation,  whether in the desert or
in the  cultivate. I  land,  uugge.st   very   different rates of
t r.,» HSBI ''sion,

      In light oi this  finding,   past studies done in Upper
Egypt now must be reexaaaiued  iu   order  to determine if the
villages saaplod were "desert  type",  "non-desert type", or a
combination of both.  In turn,   it  is  necessary to determine
t lie exact diM.i ib>it iou of the  rural  population between these
t*»o village type.'.; in Upper   Egypt  so that results from these
areas  can   b<->   Appropriately    weighted.    Without  this
icfor mat ion , which unfortunately  is  not  currently available,
prevalence figure- cannot be   re;adily  applied to the general
area.  Ideally, samples in future  surveys should be selected
to  be  rppreseri ative  oi   the   distribution  of  the total
population arnosig : U« various  village types.

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                               Schistosomiasis
      Egypt  has   had   a   progressive   program  for  the
installation of publicly accessible protected water supplies
since the early  1950's.   Of  all  the  villages sampled in
either the downstream or  Nubian  study, only in Kazan Sharg
(1) were protected  sources  of  water  totally absent,  Now
standpipes are present  throughout  the village, supplied by
the new Aswan Water Treatment Plant,  Barout  (15) and Bimban
(10)   were  the  only  other  villages  which  did  not have
standpipes and depended heavily  on water from shallow wells
where hand pumps had been installed,

      When available,,  protected  sources  of  water, either
from standpipes  or  froca  hand  pumps,  were  preferred for
drinking over unprotected sources and were used heavily (see
Tables  41,  45),   However,  these  sources  seemed  to  be
inadequate for other uses  in  Upper-Middle Egypt and in the
Nile  Delta  where  activities  such  as  bathing,  laundry,
etc.  were still frequently  carried  out  in the canals.  In
particular, water use for aniial  care and cleaning, in most
cases, involves  exposure  to  highly  contaminated sources.
The Egyptian felaheen take  pride in keeping their livestock
clean,  especially  the   domestic   water  buffalo,  common
throughout  Egypt,   later  buffalo  require  frequent dips,
According to Farooq et  aj._,,  (1966)   this is not an activity
dene solely by adult men  but involves both sexes, including
the younger age groups.  It  would seem that alternatives to
the unprotected  canals  as  water  sources  for animal care
would be difficult tc formulate.   This must be kept in mind
as  a  water-related  behavior  with  a  high  potential for
exposure to schistosoae infection even when protected public
sapplies are readily available,

      It  has  been  shown  in  this  study  and  in  others
(Farooq,et al_.  1966a;  Unrau,  1975)   that  protected water
supplys     strongly    influence    the    prevalence    of
schistosoraiasis,   The   prevalence   of   both  species  of
schistosoaes in the Nile  Delta  was  shown to fee related to
the quality of the  water  source. A gradient of improvement
in prevalence was seen  as  the  quality of the water source
improved.  This was  very  dramatic  in  the saaple sites of
Upper-Middle Egypt where  there  were more possibilities for
different  sources  of  domestic   water*   In  Upper  Egypt
protected sources were  utilized  even  more intensively for
most water-related  activities.   Infection  in  Upper Egypt
(excluding Eimban  (10))  with  schistosomes,  although much
less than in  the  ether  areas,  is probably being acquired
during  the  period  when  the  domestic  animals  are being
washed.  In  the  region  of  the  Aswan  study  sitesf this
activity invariably takes  place  in  the  Nile itself, and,
like most large streams,  the  river  is an inefficient site
for transmission.            -,«,-

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           Distribution of f. mansoni arid the AMD
      Becent studies (Almy  and  Cline, 1977) have indicated
that the  distribution  of  S^  S§D52Si  is  changing in the
southern-most areas of the Nile  Delta, and  that this may be
a result of  controlling  the  Nile's  discharge by the AHD.
Furthermore,, there  has  been  speculation   that  S± lansoni
infections have  already  invaded  areas  south  of the Nile
Delta,   The  hypothesis  is   that  the  annual  flood  had
restricted the Bi2S£^lIa£±3 species  to the  calmer waters of
the canals and drains of  the  lower Nile Delta, whereas the
less delicate BuljLnus  group  was  able  to  establish itself
throughout the country.  Hhile this is a widely held belief,
there  is  no  evidence   to   show   that   the  ecology  of
S42I£il^I§£il  i-s  solely  dependent  on  water  discharge or
velocity,  The concern, however, is well founded in that the
spread of S± jansojii  infectious  to  new areas is a serious
threat if the prevalence patterns  of the Nile Delta are any
indication of what sould  happen  if  this snail species did
indeed expand its territory,

      In  Beni  SuefF  twenty   persons  were  positive  for
.sU Bansgni ia their  stool  specimens, less  than one percent
of  the  sample,   Hhether   or   not  this  indicates  that
JLt JSSsoni has established a focus of infection south of the
delta remains to be  confirmed.   The  presence of the snail
host, Jioj£hala£i^? has not been investigated.  Furthermore,
it cannot fce  stated  for  certain  that those infected have
acquired the S_. fansgni parasites  in  the Beni Suef area or
in the north during  trips  to  the delta.   Thirteen persons
were detected with J.,  fiansoni  infections in 1972 (Hussein,
1972) , in the same  study  sites.   If these infections were
acquired in Beni Suef then  there  is reason to believe that
S_« SL§iL§ojii infections could  be found thoughout Upper-Middle
and Upper Egypt.   Indeed,  S,_  !§osoni infections have been
reported to tc very  prevalent  (60S)   south of Egypt in the
Gezira irrigated area  of  the  Sudan  {Hebbe, 1972)  and are
found  consistently   throughout   the   remaining  southern
portions of the Nile  river  basin.  From this prepective it
would seem ceasonalbe that  S._ J§nscni infections would have
always been distributed along the entire length of the river
valley*  However,  oo  one  has  yet  explained  the limited
distribution of S± SSflsosi infection  in the Nile Delta that
has been sees ia  the  past.   Scott  (1937)   was intrigued by
the sharp deaarcation which divided the regions of the delta
into areas of high and  low infestation with S_* mans2a_i«  He
could not find any noticeable change in the  topography or in
the systems of irrigation between  these areas.  Nor could a
reason be found based  on  the  type  of crop grown in these
respective  regions*   He  concluded  that   there  «as  some
controlling human factor  that  would  account for the sharp
difference  seen,  although  the  areas  in  question seemed
deraographicalIf homogeneous  to  each  other*   The point is

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that any J^ jansoni  infections  detected  in areas scuta of
the delta,  can  not  be  explained  totally  ty  changes in
hydrology.  A fuller  understanding  of  the  life cycle and
biology of the parasite  is necessary before conclusions can
be drawn  afcout  how  the  construction  of  the  AHD may be
affecting the distribution  and  transmission of S_._ mansoni.
However, the possibility  of  sporadic cases in Upper-Middle
and Upper Igypt remains and must be investigated.
            General Estimates of Schistosomiasis
      It is very  desirable  to  use  the  findings Lrom  the
three  different  areas   (four  including  Nutia)   tor which
prevalence figures fcr schistosomiasis have been obtained to
calculate estimates  of  prevalence  for  the  general iracal
population.  This must  be  carefully approached for several
reasons,.

      One, the technique most commonly  used iu  the past  and
eaployed in this study, i.e., the presence of characteristic
ova in the  excreta,  is  insensitive,  with unknown numbers
examined  and  classified  as   negative  who  are  in  fact
positive.  Seir, et al_.   (1952)   showed  long ago that time-
consuming and elaborate methods  reust  be employed  before an
individual can be  confirmed  free of schistosoma infection,,
Any findings based on ova  detection In the excreta  have to
be interpreted  as  underestimates.   Furthermore,  there  has
not been the necessary experimental work to shou exactly  how
underestimated  these  prevalence  figures  would   be.    The
findings of Heir et  aJU  (1952)   suggested that as many as
88%  of  those  negative  for   ova  in  the  urine  an   one
examination cculd  be  shown  to  be  positive   by  examining
rectal snips.  Therefore, any   survey using detection of  ova
ic the  excreta  as  a  method  of  prevalence detenu ina t ion
cannot  provide  an  exact  number  of  all  those  infectel.
Nevertheless, results based ou  these methods continue to bt
presented, partly because of  the  practical ease with which
data can be  obtained  and  also  because  data  based on  ova
detection are very useful  for  developing trends over time,
demonstrating differences in relative intensity  of  infection
from  one  location  to   another,  and  monitoring  control
prograas.  In addition, the  usefulness  of results based on
ova detection in the excreta can be increased by

       (1)  determining the number, of  ova  i u a  given amount
           of  excreta  and  thus  providing  a  measure  of
           intensity of infection in the individual, and

       (2)  by designing  an  ova  detect,ion  survey  to show
           incidence  (i.e.,  the  number  oi  new infections
           occurring   in   a   given   period).    Incidence
           determination  is  the   only  direct  method  of
                             148

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           revealing changes in transmission.

      Two,  the  total   rural   populations  of  the  three
geographic areas are very different.  For example, the rural
population cf Upper Egypt  is  only  17%  of the total rural
population.  This means that  any  estimate for a given area
will have  to  be  appropriately  weighted  according to the
proportion   that the area's rural population contributes to
the total.  These figures arc available from CAPIAS  (1976).

      Three, the  age-sex  structure  between  the different
areas must be controlled for if accurate estimates are to be
made.  Age-sex information is only available for 1960 and no
later.  Since tbe population has  not been stable but rather
growing rapidly  (approximately  2.1  to  2.5% per annum)  the
proportion of  the  younger  age  groups  has  no doubt been
increasing,  and  it  is  in  tnese  very  age  groups  that
prevalence is highest.  However, a  quick glance at the age-
specific  distribution  between  the  different  study areas
{seen in Figures 15,  16,  17)   would  indicate that the age
structures of the  rural populations are remarkably similar.

      Four,   an   assumption   must   be   made   that  the
environmental health conditions  arc  more  or less the same
throughout a given area tor  which estimates are to be made.
Especially important  are  the  types  of  water  supply and
agricultural practices in relation  to village type, the two
environmental parameters  shown  in  this  study  to be most
closely linked to schistosomiasis prevalence.

      Collectively, some very broad assumptions must be made
in calculating estimates from the  study sites to be applied
to  the  general  rural  population.   The  results  of  the
examination  tor  ova  indicate   only  the  minimum  number
infected  which  will   be   an  underestimate.   The  rural
population cf each area has been obtained from C&PMAS (1976)
which is the most acceptable demographic data available, but
does not provide  age-sex  distributions  in the population,
In the delta and  Upper-Middle  Egypt  an assumption is made
that the population  structure  and environmental conditions
are  similar  throughout  the  respective  areas,  with  the
exception of the Fayoum in Upper-Middle Egypt, which must be
excluded due to the ongoing schistosomiasis control program.
However, this assumption is  more  difficult to apply in the
Aswan area where environmental conditions and the prevalence
of schistosomiasis  vary  widely.   Before  estimates can be
calculated in this area,  the distribution of the population
between the "deseil"  and  "non-desert" type villages should
be known.  As  mentioned,  this  demographic information has
never  been  compiled,    Without   this  knowledge,  it  is
difficult tc choose fcotwoeu  either "desert" or "non-desert"
for a representative estiBut« or prevalence for this area of
E9YP*» because it is uot known how much of the population is
distributed in "desert"  villages  wh^re  prevalence is low.
                             149

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Assuming that the prevalence in the subsaople at Bimban  (10)
is the true prevalence  of  the "non-desert" villages of all
Upper  Egypt,  then,  at  the  risk  of  over-estimating the
prevalence for this  area,  the  proportion  positive in the
Bimban C\0) subsarople is used  for calculating the number of
infected in this area,

      With the above assumptions and limitations foremost in
mind and relying on  a  quote  from  Moser and Kalton (1972)
that says "The accumulated  insight of an experienced worker
frequently nerits recording even when absolute documentation
cannot be given",  estimates  have  been  calculated and are
shown in Table 53.  Almost  6.9 million rural Egyptians were
estimated to be infected. No doubt this is an underestimate*
and  actually  it  is  only  an  approximation  for  which  a
statement of  statistical  precision  cannot  be calculated.
Underestimation also results from  not  knowing how many are
infected in the urban  areas  where transmission is nilf but
to  which  large  nuabers   of  the  rural  population,  who
presumably carry with them a measure of infection, ha\fe been
migrating.


                          Table 53
  Estimated Prevalences for the Different Downstream Study
   Areas Based on Special Assumptions stated in the text.


Nile D
Upper-

Area
elta
Middle

Rural
Population
1976*
11,635,949
Egypt 4,772,647

Estimated
Prevalence of
Schistosoraiasis
0.420
0,267

Estimated
Number
Infected
4,887,099
1,274,297
   (oinus the Fayoum)

   Upper Egypt         3,224,260      0.227        731,907
  Total              19,582,856      0.352      6,893,303
       * CAPHAS  (1976) .
      Farooq, et al_.  (1966)  and Scott  (1937)  both increased
their estimates  based  on  corrections  for   more  than  one
examination for  schistosoae  ova.   These corrections  would
increase this approximation of overall  prevalence from  0.352
to   0.415.    Either   prevalence   figure,   corrected  or
uncorrected for false negatives,  seems  high  with regard to
                             150

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the lower prevalence figure  noted in Upper-aiddle arid Upper
Egypt.  This is because 59,2%  of the rural population lives
in  the  Nile  Delta  where  schistosomiasis  prevalence has
always been most intense,
              Secular Trends in Schistosotaiasis
      In the Review of  Literature,  all available past data
on the  distribution  and  prevalence  of schistosomiasis in
Egypt  were  presented   and   assessed  fcr  methodological
accuracy and conparability.   Whereas  it would be desirable
that  more   information,   especially   recent   data,  was
available, a  surprising  amount  of  useful information was
found.  Past data are employed iu this section to:

    1) determine the general  direction of prevalence trends
       siace the 1930's  in  the rural population downstream
       froE the AHD, and

    2) use  these  trends  to   assess  the  impact  of  the
       impoundment   of   the    Nile   on   schistosoraiasis
       prevalence,  It has  been  noted  that there has been
       widespread  speculation   that   the   prevalence  of
       schistosoraiasis  has  been  rapidly  increasing  as a
       direct result of the construction of the AHD.

      The earliest data from  the  last century and from the
early part of this  century,  collected mostly from hospital
outpatient clinics  in  the  northern  sectors  of  the Nile
Valley were  uniformly  iiigh  and  suggested that infections
were frequent and widespread.   These prevalence figures are
unreliable due to selection  biases in the sample.  Evidence
did show that S^ ia.nso.ni infections were rare outside of the
Nile Delta.  Scotf's work  (1937)  offers the first analytical
insight   into   the    prevalence   and   distribution   of
schistosomiasis, and his data are used here as a baseline to
which  all  survey  data   collected  since  that  time  are
ccnpared.

      Long  term  or   secular  trends  require  comparisons
between Scott's (1937) studies and more recent observations,
and to  maximize  these  comparisons  over time, tabulations
were  made  separately   for   each   of   the  three  major
geographical regions  of  Egypt  which  have been described.
The  results  of   this   study   and  others  confirm  that
environmental  and   age-sex   related   variables  strongly
influence the prevalence  of infection.  Significant changes
in these independent  variables  have  been noticed to occur
with greater variation  between  the  three major areas than
between different villages within  an area, and when general
estimates are made, these aspects must be born in mind,

                             151

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                          Table 54
             Nile Delta:  Percent Prevalence of
             Schistosomiasis for Selected Years.
                                  Percent
                                Prevalence
      Year       	
                 S. haematobium S. mansoni Schistosomiasis
 1937 (Scott)           53           54           83

 1955 (EBPH)           46           31           ND

 1966                  30           29           41*
 (Farooq,et al,_)

 1976                  30           20           42
 Kafr El Sheikh
       *Schistosomiasis figure for either type of
 infection.
      Table   54   shows    the   overall   prevalence    for
§-i  fa^efflatotiua,  Sj,  jajnsariJL,  and  schistosoaiasis  in  the
governorate of Beheira between  the  years of  1937 and  1966,
The data from Scott   (1937)  and  from the EMPH study (1955)
are estinates averaged from eight widely spaced locations  in
this  governorate,   The  overall  prevalence   (adjusted  for
sampling fraction and age structure) from the  Kafr El Sheikh
study villages, dated 1976  (the  year  of the  field survey)
was also included as an approximation of current information
for the Beheira area.  Results  from  Kafr El  Sheikh may  not
he truly representative of the conditions in Beheira in that
S_. jansoni prevalence has always been slightly  higher in  the
Beheira   governorate.    Therefore,   the   prevalence    of
.§-: S
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in an attempt to  establish  a  long  range plan  for  routine
surveillance, which  unfortunately  has  not been continued.
Hethodologies  used  in  the  study  headed  by   Faroog,  and
Nielsen,  (1966)  and used in  this  study are in essence also
very  alike*   While  no  quantitative  evaluations   of   the
different  laboratory  techniques  used  are  available,  the
basic approach  employed  by  all  of  these investigations,
i.e.  the  examination  of   urine  or  stool  sediment   for
characteristic ova, adhere  to  similar basic methodological
principles.  In addition,  the techniques for identification
of scrhistoscme ova are  not sophisticated, delicate,  or,  for
that matter, sensitive, procedures.  The sciiistosorae  ova  are
large, averaging 145 microns  in  length,  and are in no  way
difficult  to  £p«jci
-------
                          Table 55
                     Upper-Middle Egypt
   Percent Prevalence of S^ haematoblua by Selected Years.
               Year
                                            Percent
                                           Prevalence
       1937 (Scott)

       1955 (EMPH)

       1968 (Hanman, et

       1976 BeniSuef
                                               82

                                               36

                                               35

                                               27
      Although Faroog  (1967) did  not  specify the area that
was to be converted to perennial irrigation it can safely be
assuoed that he was referring to Opper Egypt, as by 1967 all
other areas in  Egypt  had  long  since beers using perennial
irrigation  schemes.   According  to  the  rural  population
figures fros CAPMAS {11376) shown  in Table 52 , there are 3.2
million rural inhabitants in  Opper  Egypt,  In essence this
is the population  at  risk,   Faroog  (196?) indicated that
before the AHB  was  built  the  overall  prevalence in this
population was 556.

      First, there is good  evidence  that the prevalence of
schistosomiasis  was  already  rising  in  Upper  Egypt long
before  the  AHD   period.    By   1955  the  pre\?alence  of
sohistosomiasis in the rural  population of Sohag^ where Hl%
of the total population  of  Upper  Egypt resides, had risen
from 3H to 14 2%, and ia  Aswan the prevalence had also risen,,
in  this  case  to  23?   (Wright,,  1973).   After  1955, the
prevalence had regained IOK (4%)  only in Qena,  There is no
information on prevalence for  Upper  Egypt between 1955 and
when the AHD was built*   It  is doubtful, however
prevalence renained low  throughout  this  period^
fairly certain that  pumps  (the  floating variety
earlier) and canals  were  installed  previous  to
scheoes implemented after the AHDe
                                                    that the
                                                    as it is
                                                   mentioned
                                                   the major
      Faroog's  (1967)  estimate  of  2.65  million new cases
translates to 82ft  of  the  total  rural population of Upper
Egypt.  Hhile it  is  possible  that increases in prevalence
occurred in limited areas of Opper  Egypt as a result of the
irrigation expansion related to  the AHD construction , it is
doubtful  that  82X  of  this  population  is  positive  for
schistosome ova.  Currents,  but  rather limited,? information
on  prevalence  in  Opper   Egypt   does  not  support  this
                             154

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prediction,   Oazo  and   Biles    (1^12)  found  an  overall
prevalence of 38?. In their  sample  from Upper Egypt, but  as
pointed  out  the;-;e  figures  are  fciased  because  of self-
selection, Hhichj  incidentally*   usually  tends  to elevate
prevalence estimates.  At any  rate  they  did not find even
half  the  nuiber  infected  that  was  projected  by Farooq
(1967),  The  current  prevalence  figures  used for general
estimates ii? Hpper Egypt  collected  by  this study are from
the Bimbari {10;   sc LO& rople,,   For  reasons already discussed,
the  Biiaban  $10)  sohsa%pj&  was   used  as  a  figure   for
estimating prevalence in this  region.   This figure is also
lower,  by   almost   four   tiroes^   than  Faroocj's  (1967)
predictions,   admittedly,   the   current   information   on
prevalence in  Upper  Egypt  is  not  extensive,  but  it  is
difficult tc imagine  that  the environmental conditions  and
prevalence of schistosomiasis  in  Upper  Egypt are now what
they «ere in the Mile  Delta and Upper-Middle Egypt 40 years
ago.  In this  same  --elo  it  Is  Interesting  that in 1937
Khalil and Aziro  (1937),.  during  their  original work on  the
effects of irrigation on schistosomiasis transmission, noted
an increase in prevalence ia Bimban (10) which had also been
included in their studies, from 2% to 64% (see Table 1).   It
would seen that, in Eiiaban (10)   at least, there was a burst
of infection following conversion  of  the area to perennial
irrigation.  Since that  time,  more  current data from this
study suggest *-hat  the  prevalence  has  fallen to almost  a
third of what it wa^ 39 years before.,

      The Koia Osabc plain was the   first site in the whole  of
Upper Egypt, to f?,e converted  to perennial irrigation and  was
a focus of high prevalence in an, area that was predominantly
lew  during  the  193Q8s.   It  is  hypothesised  here  that
following conversion  of  a  given  area  in  Upper Egypt  to
perennial irrigation,  regardless  of  the  specific type  of
scheme used, the;-" v,as  a  sharp   rise  in the prevalence  of
schistosomiosis,, followed fcy a  tapering off, lost likely  in
the 1960* s or 1370 {.c;..  similar  to  the other sectors of  the
Nile Valley to  the  forth-   Furthermore, the prevalence  in
Upper Egypt at the time  of  the survey* in the agricultural
villages,  Is at about the  same   level as seen currently  in
Upper-Middle  Egypt.  tut  future  surveillance  studies  are
needed to confirm this*  It  should be noted that prevalence
information hat- been bad] y needed  in this area of Egypt  for
a long time..  It is  because  of the systematic exclusion  of
Upper Egypt IB fjelr! studies  in the past three decades that
the exact developments, is  terms  of changes ia prevalences
and the causative  role  that  the  AHD  complex has played,
cannot be completely elucidated,   However, the greater body
of evidence dees sot  support  the many predictions that  the
high prevalence of, seKi^tosomlasis  in  Egypt, and indeed  it
is still very highf Is  the  result of the formation of Lake
Nasser arid tht  related  Irrigation expansions.  Rather,  the
AHD seems to have had a  limited role, if any, over the past
12 years in  Increasing  the  prevalence of schistosomiasis.
                             155

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If  there  sere  related  increases  they  were  Limited   to
selected areas of Upper  Egypt, with undetectafcle effects  on
the northern sectors of the Nile Valley in Egypt,

      The  first  hypothesis  of  this  study  is  rejected,
Evidence obtained from the  downstream  study sites an:l from
the historical data strongly indicate an overall decrease,  in
the  prevalence  of  schistosomiasi s.   The  hypothesis that
there  have  been   overall   increases   in  prevalence   of
schis tosomiasis , in the downstream  rural population, cannot
be supported.
      In concluding,  it
regains  a  potential  for
especially into the future
lake.  The lake has formed
snail vector proliferation.
made to the lake  (Dazo and
      the species  Buliiius,
should  be
  the  spread
 reclamation
  a  huge new
   According
 Biles, 1971,
   the  vector
                                      understood  that there
                                         of schistosomiasis,
                                        areas and in the  nrw
                                        habitat favorable  to
                                        to a number of trips
                                        1972; Scott and Chu,
                                         for S^ haejnatobiug,
has  been  found  throughout.   These  aspects  pose  future
potential problems for which frequent and tight surveillance
is strongly  recommended  as  a  meas'iro  t'->
changes.
                              and SchJLStosomjLasis
      Hhen the  prevalence  rates  foe  Fgypt  cited in this
study are used  to  show  trends,  the  impact of population
growth on the total  number  of  cases of schistosomiasis  is
revealed.  Because cf the increase in population, the actual
nuiaber of cases can increase  without a change in prevalence
or a change in the geographical distribution of  the disease,
This is an additional dimension of the impact of the disease
and can be illustrated as follows:

       In 1937,  Scott   (1937)  estimated  that  7.15 million
persons in all of  Egypt  were  infected  with either one  or
both species  of  Schistosoma.    (This  included 0,5 million
persons infected in urban areas.  when they are excluded the
estimate falls to . 6.65  million  cases.)  The population  at
that tine was 15.23  million  persons, making the prevalence
46.9511 (see Table 56).  If we  assume that there has been  ao
change in  prevalence  since  Scott's   (1937)  time  not any
change  in  distribution,   then   46. 95$   of   the  present
population  would  be  infected;   that  is,  17.95  million
infected  out  of  38.23  million  in  Egypt  in  1976.  The
difference   would   be   10.7    million   more   cases    of
schistosomiasis when compared  with  the  number infected  in
1935,  a  result  directly  related  to  a  rapidly  growing
population.
If  we  assume  that
there
 I 56
                                    ha
               been  =\  change
                                                           in

-------
                          Table 56
       Table Showing the fiesults of Certain Assumptions
        Made on the Prevalence of Schistosomiasis in
           Bespect to Population Changes in Egypt.
                                     Number
      Area and Year     Population  Shedding    Percent
                          (1X106)   Ova  (1X106) Prevalence
   1935 Entire            15.23        7,15      46.95
   Nile Valley
   and Delta

   1976 Entire            38.23       17.95      46.95
   Nile Valley
   and Delta

   1976 Assyut to          4.27         2,0      46.95
   Aswan Only

   1976 "Adjusted"        38.23       19.95      52.18
   Entire Nile Valley
   and Delta

   1976 All Rural Egypt   19.58        7.13       25.9
distribution in the area south of Assyut to Aswan, where  the
prevalence in 1935  was  in  the  neighborhood of 1-2%, then
there are even more cases that would have to be added to  the
current "estimated*1 17.95 Billion infected.  As pointed out,
there is  good  reason  to  think,  that  S^  i»a§l
-------
in Upper Egypt living  in "desert" villages where prevalence
is also low.

      It must also  be  remembered that prevalence estimates
for Egypt are based on findings in rural areas and that very
limited  information  is  available  for  urban populations.
This is important  because  the  urban populations have been
growing rapidly, at more  thac  twice  the rate of the rural
areas of Egypt, and in  the urban areas transmission is nil.
In 1935, 77? of the total  population in the Nile Valley and
Delta was rural.   Now it  is  just  over 53% or about 20.4U
million persons,  At  least  36.5%  of this rural population
(not including  the  Fayouni  population)   would  have  to te
shedding ova to equal Scott's  (1937)  estimates in 1937.

      This, of course, is very near the correct approximated
prevalence calculated by this study for the rural population
in  the   Nile   Valley.    The   combination  of  declining
prevalence,   rural-urban    immigration,   and   increasing
population in the last  40  years  has resulted, at least in
the  rural  areas,  in  keeping   the  number  of  cases  of
schistosomiasis constant.   From  the  urban perspective, an
observer that  has  been  seeing  tens  of  thousands of new
schistosoniasis  cases   (as   rural-urban  immigrants)  has
probably blamed the  AHD  more  than  once for this alarming
increase, when  actually  the  real  cause  for increases in
schistosomiasis in  urban  Egypt  is  in  migration, not the
Aswan High Cad.

       Whatever  the   exact   figures,  schistosomiasis  is
undoubtedly a  tremendous  health  burden  for  the Egyptian
rural population.  The  numerous age-prevalence curves cited
here  indicate  that  many  persons  who  are  not currently
shedding ova have  been  previously  and may develop chronic
manifestations.  Thus,  trends  based  on  ova  detection in
excreta do not render an  exact  figure for the total number
actually infected  but  result  rather  in an underestimate.
Nor is it known how  many new urbanites are infected. Trends
of this type  only  suggest  relative  changes in the number
infected, and, in the case  of rural Egypt, they do indicate
a decrease.   These  points  are  important  in  view of the
speculation  concerning  the  impact   of  the  AHD  on  the
transmission of schistosomiasis. The  guestion of the future
iapact of the Aswan High Dara on changing the transmission of
schistosoniasis still remains.  It is too early to know what
changes will occur in  reclaimed  lands  or in the new lake.
The exact distribution of S_. fansoni infections also remains
to be  resolved.   Additional  data  are  clearly needed.  A
review of trends presented in  this study does show that all
current  results  must  be  viewed  against  the  historical
context in which  schistosomiasis  has  existed in Egypt for
centuries.


                             158

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                      The Nubian Studjr


      Prevalence  data  for  schistosomiasis  were collected
also in  Nevi  Nubia.   The  objective  was  to  determine if
changes  had  occurred   in   the  Nubian  population  after
relocation.  Previous to the filling  of Lake Nasser and the
inundation of the Nubian  homes  these people were livinq in
an  area  over  150  kilometers  long.   Table  39  gives an
indication of what some of the environmental conditions were
in  respect  to  housing  and  water  supply.   The majority
obtained their water froa  the  Nile,  even when the Kanoose
tribe was included in the  total.  Abdady and Shalash  (1966)
noted that tany of the puaps  in the Fadiga area were broken
which means that many more  families were taking their water
from the Nile than indicated.  After resettlement the Nubian
water supply was improved, as has been pointed out.

      This  is  one   possible   reason  why  prevalence  of
schistosomiasis  has  decreased  in  this  population.   The
results from this  study  conclusively  show that prevalence
has dropped in the  Nubian population.  Zawahry (1964) found
12 years  previous,  in  the  same  villages  (not including
Kalabsha (9) and  Tushka  (6)),  that the overall prevalence
was  15.2%.   The  adjusted   prevalence  from  their  study
(including  Kalabsha  (9)   and  Tushka  (6))   was  7.2%.  If
Kalabsha (9) and Tushka (6)  were not included in the overall
prevalence figures the  improvement  would  be even greater.
This  is  because  Kalabsha    (9)   had  an  unusually  high
prevalence.  fi comparison  between  Zawahry's (1964)  results
and this study by village  (compare  Table 51 with Table 16)
shows in every case that prevalence has dropped in the sites
surveyed by Zawahry (1964).    The  «ost dramatic changes are
seen in Ballana (5) and El Malki (9) .

      Aside from the  improvement  in  water  supply, a more
iiportant parameter contributing  to  the fall in prevalence
is the change in  irrigation practices following relocation.
The Nubians had begun  irrigation  development in the 1950's
in selected areas.  Little  development  had occurred in the
northern tribes because the low lands in their area aad been
inundated by the rising  waters  trapped  by the first Aswan
dam built in 1910.  Host  of  the nembers of this tribe have
had to relocate twice this century, the first time to higher
rocky and very  hilly  ground,  but  within the same general
region, the second time  to  New  Nubia.  The hilly areas of
the first relocation were unadaptable to irrigation schemes,
and  thus  Zawahry   (1964)    found   a  low  prevalence  of
schistosomiasis.  Since the Nubians  have moved to Kom Ornbo,
their exposure  to  irrigation  systems  has  lessened.  One
reason in addition to improved  water supply is that the new
villages were constructed  strategically  at a distance from
the canals in the Kom Cmbo plain.  Hater from the standpipes
is far more convenient  than  that from the canals.  Perhaps
                             159

-------
even aore isportantly, the  Nubians  were compensated by the
government with land in the  Kom  Ombo.  As land owners, the
Nubians can and do hire locals  to till and tend the fields.
One last additional aspect that may also have contributed to
controlling prevalence  in  the  resettled  Nubians  is that
schools,  clubs,  social  centers,  electricity,  and  rural
health units and centers  were  all built into the resettled
sites.

      The findings at  Kalabsha   (9)   remain an enigma.  The
unusually high prevalence of  infection  is unique to Nubia.
The distribution of the infection  between the sexes has not
been seen in any of the  other samples in this study or, for
that aatter, in any other study.

      In  the  general  survey   of  Nubia,  there  were  no
outstanding environmental  or  demographic  features  in the
Kalabsha  (9)  study  site  that  would  provide an immediate
answer as to why Kalabsha  (9)  had a much higher prevalence
of schistosomiasis thaa any of the other villages sampled in
Nubia.  The age structure  was not unique.  The age-specific
prevalence of Kalabsha (9)  was proportionally higher in the
middle age groups  when  compared  to  the  results from the
other  Nubian  sites,  which  typically  fell  in prevalence
following the late  adolescent  and  early adult age groups.
It is possible that  older  Nubians  who had previously been
eaployed  in the Nile Delta  (or in ether northern sectors of
E(?ypt)  were  returning  and  brought  with  them  infection
acquired  outside  of  Nubia.    The  observation  that  the
roalecfeaale ratio has increased since resettlement indicates
that many  sales  have  returned  after resettlement.  Fahiro
(1974) also noted that many  of the Nubians who had migrated
to the north for work  were  returning to join relatives who
were now  aore accessible.   This explanation seems unlikely,
however.  If it  were  true  that  returning Nubians brought
schistosoae infections with them, one  would expect to see a
similar elevation of prevalence in the other Nubian villages
sampled.  The general low  prevalence detected in Nubia does
not support this explanation.

      Zawahry's (1964) results  indicated  that the tribe to
which the Nubians of  Kalabsha   (9)  belonged  had had a low
prevalence of schistosomiasis  (4.19).  However, Zawahry also
noted ten years previously, in 1954, that El Dakka, a nearby
village   belonging  to  the  same  tribe,  had  a  perennial
irrigation  project,   aad   had   a   high   prevalence  of
schistosoniasis.  Even if  it  could  be shown that Kalabsha
(9) had had an  elevated  prevalence  before being moved and
had siaply carried the  infection  over  to the new site, it
would not explain how the prevalence has been maintained for
twelve years in an area of predominately low prevalence,

      Water and wastewater practices in Kalabsha  (9) did not
differ significantly from the  other Nubian villages, all of
                             160

-------
which were provided  by  the government resettlement program
and are very siailar.  actually,  more homes in Kalabsha  (9)
had electricity (57.IS) and  cooked  with karseen (9U%) than
in any of the other villages, indicating a superior economic
status.  Usually econoaic  status  correlates inversely with
prevalence (Farooq, et al..., 1966) ,

      It is not known whether  or not the people of Kalabsha
(9) cultivate their own  land  or  hire local saidies  (Upper
Egyptians) as the  Nubians  generally  do (Fahim, 1974),  If
they do attend their  own  fields,  the  risk of exposure is
probably much greater.  This  is  an important parameter for
fcllow-up  studies,  which  are  needed  before  an accurate
evaluation of this anomaly can be established.

      Finally, the results  from  Kazan  Sharq   (1)  in Aswan
oast be considered. This village  is populated by Nubians of
the Kanoose tribe.  Because it  is located just north of the
old Aswan Dam it represents  a  Nubian village which did not
have to be relocated, either in  1910 when the old Aswan was
built, or later when the AHD was erected.

      As   shown   in   Table    35,   the   prevalence   of
schistosoniasis in this village is 6.9$, typically low for a
village with no irrigation  schemes  and  only the Nile as a
water  source.   There   were   no  other  environmental  or
demographic parameters in Kazan  Sharq  (1)  which seemed out
of place to what  might  have  been expected if this village
was  studied  12   years   previously  when  Zawahry   (196*1)
completed  the  study  on   the  Nubians  before  they  were
relocated.  Indeed, there is no  reason to believe that this
village is not representative  ot  conditions in Upper Egypt
when basin irrigation existed throughout, or even of earlier
periods.  The results froa  Kazan  Sharq (1)  could easily be
considered  as  an  ultimate  baseline  for  schistosoaiasis
prevalence in Nubia, Upper Egypt, or Egypt as a whole before
development   of   modern   agricultural   techniques.   The
iaplication is that  the  Nubians  in  their original state,
before there was any  irrigation development by the southern
two tribes very  probably  had  a  low prevalence similar to
that  in  Kazan  Shacq   (1).   During  the  1950*s,  limited
irrigation development resulted  in  sharp  increases in the
regions where these schemes  were installed.   Now, following
relocation, the Nubians are,  for  the reasons stated above,
isolated from  sites  where  there  is optimal transmission,
(with the apparent  exception  ot  Kalabsha   (9))  and, as a
population over the  past  12  years  have been losing their
infections.  Part of this loss  results from the dilution of
ac infected population  with  successive cohorts that remain
free  of  infections,   This   would  explain  why  the  age
prevalence curve for Nubia is  not  as marked in the younger
age  groups  as  would  be  expected  under  more stabilized
conditions.  Also,  loss  of  infection  could  be occurring
spontaneously  and  as  a  result  of  specific  therapeutic
                             161

-------
treatment.  Spontaneous loss probably does not account for a
significant proportion, especially in  the adult age groups,
but little is kcown about  this aspect of the disease.  Loss
of infection due to treatment may also be limited.  Specific
treatment  has  never   been   popular  because  of  various
reactions  to   the   therapeutic   agents  available.   The
observation is that over a  period of 12 years prevalence in
the southern t»o tribes  has  dropped  froa 23% to less than
5%.  It would seem in a period of 12 years, or perhaps less,
a population no  longer  exposed  is  capable  of shedding a
substantial proportion of its infection.  Hhereas there have
been many observations to  show  how quickly prevalence in a
susceptible population can  rise  from  a  very low point to
where  virtually  the  entire  population  is  infected (the
results in Table 1  are  an  example)  there is little or no
data to show how quickly  a population will cure itself.  It
is possible that the  observations  Bade in the southern two
tribes, represented by El Malki  (7) and Ballana  (6) , are an
indication cf this.  It  would  be  interesting to know what
the real  loss  rates  were.   Predictions  of  decreases in
prevalence  following  environmental  control  measures  are
badly  needed,  and,  without   this  measure,  it  will  be
difficult to evaluate such projects.

      The second hypothesis of  this study is also rejected.
The overall prevalence  in  the resettled Nubian population,
Kalabsha  (9) included, has decreased.  An overall prevalence
greater than 1531 would be necessary before an increase could
be considered.  The  estiaated  overall  prevalence was only
8.8%,

      The  decline  in  schistosoraiasis  described  here  is
encouraging.  However, there is no evidence that indicates a
continued decline in the  prevalence.  Changes are likely to
occur   and   must   be   followed.    The   infection  with
SGhistosomiasis in over  6.9  million Egyptians estimated by
this study demands continued concern.
                             162

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       carried out  in Egypt iu  the past 20 years.  Journal
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Abdel-Salan, E. and Abdel-Fattah,  n. 1972.  Prevalence and
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Alany, H.A. and Cline, B.L.     Prevalence and intensity of
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                             163

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Bachmann, G,  1965.   AssiSMjent^   re£orjt:_  Sewerage,  sejtajje
       gurif icatign   and    I>M£iS3     stations   in   the
       2ili£i ISiLlE    (EM/ES/ 70.  4.65)

Earlow, C.H.  1939.   Seasonal   incidence  of  infestation of
       the snail  hosts  with   larval   Hurran schistosones.
                                    2  :  73-81.
Eell, D.fi.; Farooq,  M. ;  Saaaan,   S.A, ;   Mallah,  M.B.; and
       Jarockiy,  L.     1967.     Transmission   of  urinary
       schistosomiasis   after   the   introduction  of  snail
       control. Ajaerican Journal  of  JLrojjical l£di£irie and
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Elagg, W. ; Schloegel, E. L» ; Maasour,  N.S»;  and Khalaf, G.I.
       1955,    S   new   concentration    technic    for  he
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       Aaerican Jojiraal  of Tropical Medicine and
            '
Eruijning,  C.F.A.   1971.     iater,   health,   and  economic
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CAP3AS. 1960.  Census  of   population.   Volume  II. General
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Carter, I. J.  1969.   Development in poor nations:  How to
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Chandler, A.C,     An evaluation of  the effects after two
       years   of  sanitary    improvement   in  an  Egyptian
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Cheever, A.W.  1968.   "A   guantitative post mortem study of
       Schistosomiasis aaijsoni   in  man."  l§§rican Journal
       2J l£2£I£3i  Medicine  and  Hygiene V]^: 38-64.

Cheever, A.W.; Kamel,  I. A.;  Elwi,  A.M.; Mosimann, J. E. ; and
       Danner,    R.     1977.     Ssiistosoma   S^risofii   and
       5i   Ji§§Ut2-fciJli   infections    in   Egypt.     II.
       Quantitative parasitological  findings  at Necropsy.
       American Journaj. o^ Tropical Medicine and Hicjiene 26
        (
-------
Dazo, B.C. and Biles,  J.E.   1970.  Schistosomiasis  in  the
       Kaicji Lake area, Nigeria.   Report on a survey made
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Eazo, B.C.  and  Biles,  J.E.  1971.   The   schistosomiasis
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Eazo, B.C. and Biles, J.E. 1971a.  Follow-up studies  on  the
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Eazo, B.C. and Biles,  J.E.  1972.   The  present status of
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Eazo, B.C.  and  Biles,   J.E.  1972a.    Investigations   on
       schistosoniasis in  Ghana,   Report   on  a  visit to
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Dazo, B.C.; Hairston, N.G.;  and   Dawood,  I.K.  1966.   The
       ecology  of   Sulinus   iruncatus  and  Bigmphalaria
       3i§*
-------
       il3J.LQf  the jjp_rld  Health Organization
       35: 293-318.

Farooq, H.; Nielsen,  J.;  Samaan,   S.A.; Mallah,  M.B.; and
       Allao, A.A.  1S66a.  The  epidemiology of Schistosojaa
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       Egypt-49   Project   area:     3.     Prevalence    of
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       35: 319-3307
Farooq, M.  and  Nielsen,
       Sch^istosoaa
                           J.
1966.   The epidemiology of
nd S. mansoni infections in
                             166

-------
       the Egypt-49 Project  area:   1.  Sampling techniques
       and  procedures  for  measuring  the   prevalence   of
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faroog, H. and Hairston,  N.G.    1966.  The  epidemiology  of
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Fogel, L.J.;  Sullivan,   D.;   and    flaxfield,  M.    1972.
       J?j^3e^olo
-------
       Schistosoaiasis haematobiuf infection in Upper Egypt
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Harinasuta,  C.;  Sornaani,  S, ;  and  Kitikoon,  V.  1972.
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Hassouma, H.   1975.   §Sliejfsx  £fac^icesx  environment and
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Heynenan, D. 1971.   Mis-aid  to  the Third Horld:  Disease
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Hiatt, B.A.  1976.   Morbidity   from  Jchi§tosoja  mans on i
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Hira, P.H. 1969.  Transaission  of  Schistosomiasis in Lake
       Kariba, Zambia.  Nature 22f»:  670-672.

Hussein,  fi.   1972.    Unpublished  mimeograph  on   health
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Imevbore, A.M. A. 1975.  Ihe Kainji Dam and health.  In i!an-
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Jordan,  P.   1972.    Schistosomiasis   and  disease.    In
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Kamal, A.M.   1952.  Bored-hole  latrines  in  Sirs-El-Hayan
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Knight, M.B. ; Hiatt, B. A.;  Clure,  E. L. ; and Hitchie, L.S.
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       concentration technigue for increased sensitivity in
                             168

-------
       detecting   Schistoso^a    JS§J3§oni   eggs.   il§cj.can
       i?2.y.£fisLL of  Trojgical   Medicine  and  H^LaiS-II6. 25  (6) :
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Khalil, fl.  1949.  The  national   campaign for the treatment
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       Schistosoma infection  through   irrigation schemes in
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Khalil, H. and  Azia,   M.A.   1938.  Further observations on
       the introduction  of   infection  with S._ haejaatobiujB
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       j32JJfi§l  2JL   *°e  ^9X£^A^n  ^§^i£a^  Association JM:
       95-1017

Lanoix,   J,H,    1958.     Relation    between   irrigation
       engineering and  Bi^Jiarziasis..   Bulletin of ^he Ho^_ld
       Health Oraanization  J8:  10"? 1-1035.

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MacDonald, G.  1955.    Medical   iaf lications  of  the Volta
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       SchistosomiasiSi   Office   of   Health.   Bureau  of
       Technical  Assistance.     Agency  for  International
       Development.   Washington,   D.C.  20523.   September
       1970.

Messina,  A.M.    1970.    Planning   of  environmental  and
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Hitwally, H.  and   El-Sharkaw,   P.  1970.    Methodology and
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flobarkic,  E.  H.     1975.     £ajrouji  Control  frojecj:  for
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                             169

-------
Moser,C.A. and Kalton, G.   1972.  Survey Mlfe2^§ iB. Social
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Sagaty, H. F.  and  Bifaat,  M.A.   1957.  A parasitological
       survey of the Kharga and Dakhla Oases in  1952 and  of
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____ .1966.   Impact  of   econoaic  development on  health
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       38: 199-202.

Eifaat,  M.A,;  Salem,   S.A.;   and  Nagaty,  H.F.    1964.
       Parasitological and serological  surveys  in Wadi El
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       haematobia  in  Egyptian   mummies  of   the  Twentieth
                             170

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       dynasty  (1250-1000  B.C.) ,  British fledrcal Journal Jh
       16-25.

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       environnental  problems — a  taxonomy.   Science J72  (25
       June):  1307-1314.
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       Jfcealth asjaectsl  Nov...  1969^Se£t.. 1970^""
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       schistosomiasi-s   in   hyperendemic   area  at  Iflaka
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                   ISJPJEl ofi s  ^isi^ fade f_£om th_e
              IS  SilM   12   i§JS§  JS2§§2S  i£  iJSforj  Coast
       MPD/24.7  »HC unpublished.

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       husean  schistosoffliasis in  Egypt.   AmSf-iciS J2J!r.Iia.;L of
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                             171

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       18-20, 25-26.

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       1JJ  (35):  611-620.

Baterbury, J.  1971.   ]|an£21§£  §S
-------
       of schist os cuiasis.   Bulletin   o£  the jtorld Health
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       the  l^YBiiaj  Public  Health   Association  39  (5) :
       313-340.
                             173

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                         APPENDIX I
                  Resource Centers in Egypt
      This is a list of  centers  in Egypt where material on
aspects of schistosomiasis aud other tropical infections may
be found.
Aoerican University in Cairo, Library; Kasar El Aini Street,
Cairo
The  Egyptian  Ministry  of  Health,  Library;  Garden City,
flagles El Shob Street, Cairo


The High Institute of Public Health, Library; 165 El Horreya
Street, Alexandria


Naval American Research  Unit-3;  c/o  D. S, Embassy, Garden
City, Cairo


Aaerican Cultural Library; Garden City, Cairo


Cairo University Medical Library; Gi-za, Cairo


British Cultural Library; Dokki, Cairo


icrld  Health   Organization,   Library;   Regional  Office,
Alexandria
                             174

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                         APPENDIX II


                         DATA FORMS


                CLINICAL EXAMINATION FORM 01


Code:  Village ID ...... Family Id ...... Date

Name and ID code ....
  Relation to head cf household
  Sex
  Date of Birth
  Age
  Sunber of Years in Village
  Marital Status
  Number of Pregnancies
  Nufflber of Live Births
  Humber of Still Births

  Most fiecent Medications/Date;

  First Diagnosis
  Second Diagnosis

  Urine Specimen
     S. haeaatobium
     S. mansoni

  Height (c»)
  Height (kg)

  comments

  Education
     Preschool Age
     School Age Not Attending
     Does Not Bead or Write
     Beads Cnly
     Reads and Writes
     Has Conpleted Priaary School
     Has Completed Secondary School
     Has Received Higher Education
     No Information
                            175

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 Occupation
    None
    Landowner (Non-Farmer)
    Farmer
    Farm laborer
    Fisheroan
    Boatman
    Domestic Servant
    Skilled laborer
    Other Manual Laborer
    Clerical
    Professional
    Housewife
    Tourist Guide
    Other
                      HOUSING FOBfl 02
Date
Village
Dame of Owner
Address
Year House was Built
1.  Construction material
    stone or red brick   1
    sad brick            2
    wood or reed         3

2»  Structure attachment
    detached             1
    one side only        2
    two sides            3
    three sides          4

3,  Painted walls
    exterior             1
    interior             2


-------


7,


8.






9.




10.
11.



12.


13.
14.

15,



16.


17.



18.


reed
mud
Roof condition
permeable
not permeable
Storage place for
fuel materials
roof
stable
storage room
yard
none present
Floor construction
earth
concrete
tile
wood
Number of windows ..
Lighting
electricity
kerosene
other
Television
present
absent

Number of persons
living in house . .
Stable
inside
outside
none
Waste container
yes
no
Animal waste materia
stable 1 canal
yard 2 roof
street 3 none
Cooking fuel
gas
oil
3
4

1
2


1
2
3
4
5

1
2
3
4
* *

1
2
3

1
2


• *

1
2
3

1
2
1
4
5
6

1
2
177

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     wood                 3
     dung                 4

19.  Stable cleaning
     daily                1
     weekly               2
     monthly              3
     never                4

 Form continued on next page

20.  Housing approach
     non-earth:
     clean                1
     littered             2
     dry                  3
     wet                  4
     earth:
     clean                5
     littered             6
     dry                  7
     wet                  8

21.  Screens
     yes                  1
     no                   2

22.  Hosguito nets
     yes                  1
     no                   2

23.  Ownership
     own                  1
     rent                 2

2U,  Halls decorated
     inside               1
     outside              2
     none                 3

25.  Water source
     public               1
     private              2
     surface              3
     ground, well         4

26.  Hater supply drinking bathing laundry utensils aaiaals

     piped
       inside
     piped
       outside
     hand  punp
       inside

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     hand puap
       outside
     canal
     drain
     lake or
       pond
     Hirer Sile

27.  Storage of water
     metal               1
     ceraaic             2
     earthenware         3
     other               4

28.  iastewater drainage
     concrete            1
     pipe                2
     trick               3
     tile                4
     earth               5
     other               6

29.  Latrine
     yes                 1
     no                  2

30.  Is the latrine used?
     yes                 1
     no                  2

31.  Is there a cover
       for the latrine?
     yes                 1
     no                  2
     Date of latrine
       installation.......

32.  Type of latrine
     borehole            1
     pit                 2
     masonry walls       3

40.  Water carriage present
       in the latrine?
       yes               1
     no                  2

34.  Septic tank
       present?
     yes                 1
     no                  2

35.  Cesspool present?
     yes
                            179

-------
     no                  2

36.  Location of
       latrine
     inside              1
     outside             2
     stable              3
                            180

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                       BE1L FOEM 03
location Information:

\illaqe ID number
Eate
Sell ID NuBber
Type of well


Depth of water level

Diameter

number of months a year dry

Date of installation

State of repair

Nearest latrine or wastewater disposal in aeters

Approximate number of users per day

Erainage

     concrete
     brick
     tile
     earth

Use

     drinking water
     drinking and washing
     washing only
     not used

Contamination of well water with drainage possible?
                        181

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                       CANAL FORM 04
LocatioD Inforaation:

tillage ID Number
rate
Canal ID number
Date of construction

length

8idth

Depth

Approxiaate discharge    a3/day

Irrigation canal:  nuaber of feddans irrigated


Dse:

    drinking water supply (public use)
    drinking water
    bathing
    laundry
    washing utensils
    washing aniaals
    swimming
    wastewater disposal
    sewage outfall present
    aniaal waste disposal

Septic

Canal lined with concrete or tile
                          182

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                      MOSQUE FORM 06
Location Inforaation:

Killage ID Number
Date
flosgue ID Nunber
Mosque Name
Date of construction

Construction material

    stone or red brick
    oud brick
    wood or reed

Interior yard and floor construction

    stone or tile
    reed
    earth
    concrete
    wood

Electricity

iater supply

    public (piped)
    private:   surface   ground

Drainage of wastewater

    concrete
    piped
    brick or tile
    earth
    other

Drinking water

    piped
    stored
      aetal container
      cerasic container
      other
                         183

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Latrine
    present
    cover
    date of installation
    type
                          184

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                      VILLAGE FOfiM 07


Location Information:


Village ID Number

Village Naae

Goveruorate

Area

Latitude

Longitude

1.  Population 1976

2.  Total cumber of houses 1976

3.  Street sanitation

    Always free of solid waste and litter
    Has regular collection of solid waste
    Paved (% coverage)
    Large collections of solid waste present
    Hastewater and/cr aud present

1.  Public lighting

    Electric
    Oil
    None

5.  Solid waste collection service available for homes?

6.  Public treated water supply   yes   no

    ground water   surface water
    demand
    number of water points—outside     in hone
    number of taps working
    chlorination    yes   no

7.  Ground water levels

8.  Public wells              Private wells

9.  Climate
                          185

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10*  Terrain—elevation from sea level, etc.



11.  Agricultural practices and general economy
                         186

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                    HATER POINT FORM 09
Location Infornation:

Village ID Hunter
Date
Water Point ID Number
Number of taps

Number of taps working

Date of installation

Source of water

    well
    treated
    other

Drainage area

    concrete
    brick
    earth

Number of hours/day with flow

Approximate number of users per day

Dse

    drinking
    drinking and washing
    washing only
    cooking
    not used
                        187

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                   LAKE AND POND FORM 10
Location Information:

tillage ID Number
Date
Lake or Pond ID Numter
Size

    length
    width
    depth

Seasonal Hater levels

    winter
    spring
    summer
    fall

Dse

    drinking water
    bathing water
    laundry
    washing utensils
    •ashing animals
    swinging
    wastewater disposal
    sewage or latrines
    solid waste disposal
    aninal waste disposal

Number of drain outfalls present

Septic
                        188

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               HATEB TBEATWENT PLANT FOfiM 11
Location Information:

Village
Date
Village ID Number
1.  Location of plant

2.  Date when plant first began to operate
    How long has the plant been operating?

3.  Population serviced:

    a.  Does the plant serve the entire village?
    b.  Does the plant serve less than the entire village?
        If sc, how such is covered?
    c.  Does the plant serve other villages or places
        besides the village?  industrial sites?

4.  Give location of the source of water used by the plant
    for treatment

5.  Obtain the volume of water treated by the plant:
    daily

    yearly

6,  Describe each point where chlorination of water is
    carried out currently in the treatment process.

    How much chlorine is being used?


7.  Are there laboratory facilities to check the quality of
    the treated water?  untreated?  describe...

8.  On the average how many hours each day does the
    distribution system have pressure?

9.  Is there a water storage tower present?  capacity?
                            189

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                        APPENDIX III


                  CODE KEY AND CODING F08MS


 CLINICAL CODE KEY


 1.  Clinical data code form number = 01

 2.  Code nuaber of unit 01 to 20

      01 Kazan Sharg
      02 Guzaira
      03 Abu Rish bahri
      04 Ga'afra
      05 Ballana
      06 Tushka
      07 11 Halki
      08 Kurta
      09 Kalabsba
      10 Biaban
      11 Barout
      12 Sherif Pasha
      13 Naiist
      14 Beni Adi
      15 Ashaant
      16 El Agazein
      17 El Hamra
      18 Mahalet El Kasab
      19 Hahalet Mousa
      20 Sheno

 3.  Fanily code number from 0001

 14,  Code number of person within the family from 01

 5,  Question 1:  Relation to the head of the faaily
     1.   Head of Faaily
     2.   Sife
     3.   Sale offspring
     4.   Female offspring

 6.  Question 2:  Sex of the person or individual
     1.   Male
     2.   Female

 7.  Question 3:   Date  of  birth.   Use  only the last  two
digits of the year of tirth.
     1943	43
                             190

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     99 = co information
     Question 4:  Age of the person or individual
     Code for age gr.cups
     00 - 01
     01 - 02
     05 - 03
     10 - 04
     15 - 05
     20 - 06
          07
     25 -
     30 -
     35 -
     40 -
     45 -
     50 -
     55 -
     60 -
     65 -
          08
          09
          10
          11
          12
          13
          14
          15
     Example:
     recorded on data fora as age group 25-30
     group code number = 07
 9.  Question 5
in this village
                  Number of  years that individual has lived
                  Recorded directly as number of years.
 10. Question 6:  Marital status of individual

     1 Single
     2 Married
     3 Divorced
     a Widowed
 11.  Question
information
 12. Question
information
 13. Question
information
 14. Question 10
infection.
                     Number  of  pregnancies    99  means no

                                           0 means none

                    Number  of  live  births    99  means no

                                           0 means none

                    Nuaber  of  still  births   99  means no

                                           0 means none

                    Drugs  taken  for treatment of parasitic
     Blank on data fora means no information = 99
     Drugs or medication  given  fcr  other infections means
     other =37
     No medication or drugs received means none = 0
       (This may be recorded on the data form as a slash)
                             191

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     First two boxes are  for  month  of  year when drug was
     given
     Third box is for the year   1975 = 5

 15.  Question 11:  Diagnosis of individual

     A special code list is to be prepared

 16.  Question 12:  Same as question 11.

 17.  Question 13:  Examination for S._ haematobium infection

     Positive = 1
     Negative = 2
     No specimen

 18.  Question 11:  Examination for S± JSansoni infection

     Positive = 1
     Negative = 2
     No speciaen = 3

 19.  Question 15:  Deleted

 20.  Question 16:  Deleted

 21.  Question 17:  Height of individual.  Record directly as
height.
     Last column for fraction

 22.  Question 18:  Height of individual

     56 kilcgrams; record as 0560
     56.5 kilcgrams; record as 0565
                             192

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23.  Question 19:

    The individual  has  not  attended  the examination =no
    response = 1
    The individual is no longer living in the village = 2
    The individual has died = 3
    Form is blank for question 19 = 99
    Stool specimen given = 4

24.  Education of  the individual

    Record the number given
    If question is blank = 99

25,  Question 21:   Swianing and bathing habits of the

    individual
    Record directly the number or numbers given
    Example:  4 is recorded as 0004
              1 and 4 is recorded as 0014, etc.
              Use combinations.

26,  Question 22:   Occupation of the individual

    Record directly the number given in the same fashion as
    in question 20.  If  the  question  is blank = 99 Note:
    Additional occupations not listed  on the data fora may
    be written in the space  for  the code number.  In this
    case the occupation should be  listed in the code guide
    and given  a   code  number  and  recorded  in  the same
    fashion as above.
                             193

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                         APPENDIX IV


                       Guide for Field Survey


                 Standard Methods for Survey


         Protocol for Selection of Sample Population
1.  A faaily is  a  nan  and  his  wife (s)  and all unmarried
children.  Single adults (if  selected)  who have no parents
constitute a family.  If a single adult living away from his
parent(s) is selected,  the  parent (s)  must also be located
(only if living in the  same  village), as well as all other
unmarried children.

2.  It is net desirable to examine persons not selected from
the sample frame.   HOWEVER:  older persons, village leaders
and well known respected persons  that desire to be included
should be INVITED to the  exam,   DC  not give a family code
number to these families or persons,

3.  If a selected family  member  is missing but will return
to the village before  the  end  of the survey, complete the
exam for all other  family  members,   but hold clinical form
until the missing  family  member  returns and then complete
the form by examining the remaining member.

4.  As families are selected  from the sample frame they are
simultaneously assigned a serial number starting with 0 0  1.

5.  This serial number automatically becomes the family's  ID
cede number and the ID code number for the family's house.

6,  After each family is examined, their name is checked off
the sample frame.
                             194

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                Clinical Exam Boutine Outline
1.  Before a selected  family  comes  to the health unit  (or
center) a visit must be  made  to  the home of the family by
the health team engineer-sanitarian in order to:

      a)  Inform the family about the clinical exam and that
          all members of the family should attend regardless
          of age or disability.   (For those too disabled to
          leave the hose the  team  from the unit must visit
          the hone, carry out the clinical exam, and collect
          urine and stool samples)

      b)  To  inform  the   family   that  urine  and  stool
          specimens will be necessary at the health center.

      c)  Tc complete the housing data form.


2.  The first step  once  the  family  arrives at the health
unit or center is for the doctor to enter the family ID code
number on the clinical exam  form 01 and the individual code
numbers.  The individual  code  number  is  at the left hand
margin where the individual's  name  has been entered on the
data fora.  Each individual  then  will  have a 7 digit code
number comprised of the  two  code  numbers for the village,
three for the family, and the last two for the individual,

CAUTION:   Always  take   great   care  to  avoid  confusing
individual ID numbers.
3.  The nurse,  assistant,  or  physician completes the data
form which is non-medical,  i.e. occupation, education, age,
etc.
4.  Urine specimens must  be  taken from each family member.
The laboratory technician makes  sure  the specimen is given
and placed in the correctly labelled container.  The results
of the examination of  the  urine  are entered onto the data
form.
5.  Stool specimens must  be  taken  from each family member
(cnly  a  small   volume   is  necessary) .   The  laboratory
technician copies the  individual  ID  code  number from the
person givirg the specimen  on  to  a plastic stool specimen
vial.  The stool  specimen  is  transferred without del.ax to
the correctly labelled specimen vial according to protocol.
                             195

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6.  The weight and  height  of  each  family member is taken
according  to  the  protocol   given  and  recorded  in  the
appropriate place on the clinical exam data form 01,


7.  A physical exam  of  each  family  member is made by the
physician.  A first and  second  diagnosis  is made and tais
information is entered  into  the  appropriate spaces on the
data form.
8,  The medication that may have been received previously is
a  very  important  aspect.   This  will  require  that  the
physician cross-examine the  person  until  it is determined
what, if any, medications have been taken.  Only medications
for parasitic diseases are of interest.
                            196

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 9.  Please note that blood films Kill not be taken,
10.  Check cff the family  name from the sample frame.  This
will prevent seeing the same family twice and will help show
how many faailies have been examined.


11.  Following the  completion  of  the above activities the
examination of the family  ends.   Go  to the next family on
the sample frame.
                             197

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                    TECHNIQUE FOR PLACING
             THE PEBSON IN THE CORRECT AGE GROOP

            DC NOT ATTEMPT TO ESTIMATE EXACT  AGE

     00-01
     01-05
     05-10
     10-15
     15-20
     20-25
     25-30
     30-35
     35-40
     40-45
     45-50
     50-55
     55-60
     60-65
     65 *

     Note:  This guide is to  be  used when the person  to  be
exaained has no  record  of  birth  date or government-issued
identification card.
                             198

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            METHOD FCfi COMPLETING THE DATA FOBMS


                    CLINICAL EXAM FOfiM 01


Enter village  ID  code  number  in  box  given  and fill in
village name.

Enter the family  ID  code  number  in  the box given.  This
number has be the sane as the house ID code number where the
family lives,

       NOTE:  One form is  to  be completed for each family,
       even if the family is only a single person,  A family
       is a man and his  wife(s)  and all unmarried children.
       Single  adults  (if  selected)   who  have  no parents
       constitute a family,  If  a  single adult living away
       from his parent is selected, the parents must also be
       located Jonly if living in the same village), as well
       as all other  unmarried  children.  The entire family
       is then examined and  all  results are entered on the
       same clinical exam form 01.

Enter data in box given:   day month year.

The  name  of  each  family  individual  is  entered  on the
clinical exam  form  01.    Each  member  of  the family then
receives  a  tag  with  the   village  ID,  family  ID,  and
individual ID code  nuaber  written  (in  this order)  on the
tag.  The individual's ID code number is taken from the left
hand margin of the clinical exam form where the individual's
name has been entered,

    There is no given order  iu  which to complete the form.
This  is  left  to  the  team  to  nanage  and  to  suit the
organization at the health unit or health center.

    The following is a guide to each entry:

     1)   Relation to head:  Hrite  in  the appropriate space
         the relation to  the  head  of  the family for each
         mesber.

     2)   Sex: enter male or female in the given space

     3)   Inter date of birth  by  year  only.  This is to be
         confirmed  by  checking  the  government-issued  ID
         card.

     4)   Enter the  age  given  by  the  individual.  Do not
                             199

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    compute age.

5)   Enter in the  correct  space the approximate number
    of years  tbe  individual  has  been  living in the
    village.  Confirm by checking on the location where
    the individual was born,

6)   Marital status:  enter in  the correct space single,
    married, divorce, or widowed,

7)   Enter  in   the   correct   space   the  number  of
    pregnancies.  If male or unmarried enter 0.

8)   sarce as above.

9)   same as above.

10)  Medication received:   This  cannot  be left blank.
    Each person must  be  thoroughly checked.  If there
    has not been any  medication received enter NONE in
    the correct space.  If  medication was received for
    illness  other  than   parasitic  infections  enter
    GTHEE.  If medications  have  been received for any
    parasitic disease, especially  for bilharzia, enter
    name of drug received, and give month and year.

11)  Enter the first and second diagnosis in the correct
    spaces.

12)  Same as above.

13)  Orine:  If the  results  from the urine examination
    are negative for £_.  ka§iaatobiuB  enter  a 0 in the
    given space.  If positive, enter  a 1.  Do the same
    for §_. fflansoni.   NOTE:   all ova must be positively
    identified as either S.. hjaematobium or S*_ man son i.

14)  Same as above.

15)  Blood films:  Originally,  blood  films  were to be
    made.

16)  Same as above.

17)  Height and Height:   enter  each measurement in the
    given space.  Refer  to  standard methods guide for
    the neasurement of height  and  weight to make sure
    that the data is  obtained according to the desired
    technique.

18)  Same as above,

19)  cosments:  This has been provided for the physician
    in charge.
                         200

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20)  Education:   Eater  a  1  for  each positive answer.
    Make sure that score  is  placed in the correct row
    and column.

21)  Swimaing:   ASK  "Where  do  you  swim  or bathe?".
    After entering  the  answer  in  the  correct given
    space ASK  "Where  else  do  you  swim  or bathe?".
    Continue  asking  this  question  until  the person
    states that there are  no  other places where he or
    she swims or fcathes.

22)  Occupation:   After  inquiry,  enter  1  under  the
    correct occupation in  the  space given.  Make sure
    that the score  is  placed  in  the correct row and
    column,

23)  Stool specimen:  Enter  a  1  if stool specimen has
    been given.   Always  double  check  to  see if the
    individual  has given the specimen.
                         201

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                 Orine Examination Protocol
1,  The entire voided urine is collected in a conical flask.
The flask is numbered with the individual's ID code number.

2.  The urine is  allowed  to settle without disturbance  for
SOninutes.

3.  A clean pipette is  used  to  collect the sediment and a
drop of the sediment is placed  on a clean glass slide,   Two
more drops  are  placed  into  an  empty  but coded specimen
bottle.

4.   The  slide  is   examined   under  the  microscope   for
schistosome eggs,

5»  A specioen is  not  negative  until all the sediment  has
been examined.

6.   ALL  OVAL  MOST  BE  POSITIVELY  IDENTIFIED  AS  EITHER
Sj. HAEMATOBIUM  OR £_. MANSCNI.
                              202

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            PROTOCOL FOR HANDLING STOOL SPECIMENS
1.  The stool specimen  is  received.   The ID number of the
individual giving the specimen  is immediately copied onto a
bottle with a felt-tip pen,

2.  Stool is placed  into  the plastic stool specimen bottle
in the following manner without delay.

 a)   Open the bottle and remove  the inner plastic cap.  Add
     a few drops of 8IF.

 b)   8ith a snail wooden palo  stick place very small pieces
     of stool  in  the  bottle  on  the  bottom.  Each piece
     should be selected from  a  different area of the stool
     speciffen.

 c)   About one c.c. of  stool  should  be transferred to the
     bottle.  This may require 8  to 10 pieces and should be
     about the same amount as a "foul" bean,

 d)   Add a  few  more  drops  of  MIF  solution  and mix the
     specimen until all the stool has been completely broken
     up.

 NOTE:  Two drops or .1 ml  of urine sediment from the urine
 specimen should also fee  added to the correct corresponding
 stool specimen bottle.
 e)   Add ?!IF  solution  until  the  bottle  is  almost full.
     Leave the neck of the bottle empty.

 f)   Place the  white  plastic  inner  cap  inside the black
     outer cap and then place both over the top,

 g)   Carefully rock the inner cap  into place with the black
     cap.  Then remove the black cap and make sure the inner
     cap is firnly in  place.   Pressure can be applied with
     the black cap if  the  inner  cap  is  still not in the
     desired position.

 h)   Becheck and make  sure  that  the  label is the correct
     label.  The bottle is now ready to be transported.
                             203

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     TECHNIQUE FOR THE MEASUREHENT OF HEIGHT AND WEIGHT


 1)   All selected  family   members  are  to  be  weighed and
     measured for height regardless of age or disability.


 2)   Procedure for the determination of weight.
      a)  each member is  weighed  with  a  minimum amount of
         clothes and without  shoes.   (NOTE:  regardless of
         how such clothes are worn during weighing make sure
         that all wear  the  same  amount  of clothes during
         weighing.   Do not  allow  one  person to be weighed
         fully clothed and then weigh the next half clothed.
      b)   Infants that cannot  stand  unsupported  are to be
          weighed with the mother  after the mother's weight
          has been taken  and  recorded.  {Infants should be
          clothed  only  in  diapers)    When  an  infant  is
          weighed in  this  manner  he  total  weight of the
          aether and child is recorded.
      c)   Check  each  week  that  the  scales  are  working
          correctly by weighing known standards,


 3)   Procedure for the deter mi nation of height.


 Adults

      a)   Place the tape in a  convenient place on the wall.
          The person's heels,  buttocks, shoulders, and back
          of head should touch the wall.  The tape should be
          directly behind the head.

      b)   Remove all head gear  if  it  has not already been
          removed.  This  includes  turbans/  hats, scarves,
          etc.

      c)   Place a right angle  (book,  etc) against the wall
          and press down to  the  top  of the head.  Contact
          has to be made with the top of the head.

      d)   Becord height to the nearest 0.5 cm.

Infants
                              204

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a)   All infants who  cannot  walk  are  to be measured
    lying down.

b)   This  will  require   two   persons  to  take  the
    neasurement.

c)   One person holds  the  head  firmly  against a 90°
    upright.

d)   The other person  straightens  the body by holding
    the ankles together with  one hand, while with the
    other  hand  the  90°  sliding  upright  is placed
    firmly against the infant's feet.
                       205

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                                  TECHNICAL REPORT DATA
                           (Please read Instructions on the reverse before completing)
1  REPORT NO.
  EPA-600/1-78-070
                             2.
                                                          3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
SCHISTOSOMIASIS IN RURAL EGYPT:   A Report of U.S.-
Egyptian River Nile and Lake Nasser Research  Project
             5. REPORT DATE
              December  1978
             6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
F.D. Miller,  M.  Hussein, K. Mancy, and M.S. Hilbert
                                                          8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
University of Michigan
Ann Arbor, MI  48109
University of Alexandria
Alexandria, A.R.  Egypt
             10. PROGRAM ELEMENT NO.
                1BA609
             11. CONTRACT/GRANT NO.
               Special Foreign Currency
               Project No. 03-542-1
12. SPONSORING AGENCY NAME AND ADDRESS
Environmental  Research Laboratory—Athens , GA
Office of  Research and Development
U.S. Environmental Protection Agency
Athens, GA  30605
             13. TYPE OF REPORT AND PERIOD COVERED
               Final
             14. SPONSORING AGENCY CODE
               EPA/600/01
15. SUPPLEMENTARY NOTES
16. ABSTRACT
      The  objectives of this study were to provide  current information on the prevalenc >
of schistosomiasis  throughout Egypt, to establish trends in the prevalence of schisto-
somiasis  in order to shed light on the potential changes caused by the Aswan High Dam,
and to determine correlations between certain environmental variables and the preva-
lence of  the  disease.   Prevalence was invariably higher in male adolescents with the
differential  between sexes increasing from north to south.  The prevalence was  signifi-
cantly lower  in those  villagers who obtained water  for domestic use from protected
supplies.  The effect of population growth and migration from rural to urban areas is
discussed.  Results based on trend analysis of  current and past data indicated  a strong
decline in overall  prevalence of the disease in rural  populations over the past 40 year
The data did  not show  an increase in the overall prevalence of schistosomiasis  follow-
ing the construction of the Aswan High Dam.  The Nubian population also experienced a
decrease in prevalence following relocation, with some villages benefiting more than
others.  Environmental conditions were also correlated against schistosomiasis  preva-
lence and  additional aspects of transmission is discussed.
17.
                               KEY WORDS AND DOCUMENT ANALYSIS
                 DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS  C. COS AT I Field/Group
Disease Vectors
Infectious Diseases
Schistosomiasis
Public Health
                               06F
                               13B
13. DISTRIBUTION STATEMENT

RELEASE TO PUBLIC
19. SECURITY CLASS (This Report)
  UNCLASSIFIED
21. NO. OF PAGES

      224
                                             20. SECURITY CLASS (This page)

                                               UNCLASSIFIED
                                                                        22. PRICE
EPA Form 2220-1 (9-73)
                                           206

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