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
-------
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
-------
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
-------
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
-------
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
-------
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.
-------
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
-------
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
-------
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
-------
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
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60
70
80
61
72
60
0
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3
a
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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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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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32
-------
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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35
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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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37
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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
-------
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
-------
(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
-------
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
-------
"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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Figure 12. A "floating pump station" in Qena.
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
0
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
32
30
28
26
to 24
Z
O 22
2
Z
z
o
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Q.
20
18
16
12
10'
8-
6
A
Z
0
INCREASE OF POPULATION
IN EGYPT= 1800-1970
TOTAL POPULATION
RURAL POPULATION
CROPPED AREA
CULTIVATED AREA
1800 10 20 30 40 50 60 70 80 90 1900 10 20 30 40 50 60 70
34
-32 !
28
o
22°
18
MAX CROPPED
AREA
12
•
-------
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
-------
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
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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.
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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.
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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.
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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
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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
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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
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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:
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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.
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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
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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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102
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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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
L)
f£
UJ
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
Q.
\n
u_
o
I
o
15
a.
AGE CYEARSD
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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118
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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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
o
-p
fp j f
•H 0)
.c i
rfl 'd
t— 4 *"*
Q) -P
15 'Si
1) C!
P 3
•C 3)
,-w
IT p
--I -r-t
CD U
F— 4 •+•* i4/
-a (t) u
«j iJ ^
p OJ
-p T)
•H >
3 CD
j_l
w a
cu
a 1/5
o -^
o e
c
ii T.
tr^ o
Tj t-'
P Ifl
c! H
U ^rj
0 0
M -0
ri!
e
=>
•H
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01
rtj
e
cu
r(3J
j^j
'!
OJ
•rH
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O
0,
l)
>-"
(TJ
"
0)
CT
to o
ro r^
r~
T"~ ^^
• •
LP -^
vO ^>
r^j r^*
^> ^
^ r^
T—
P
C P
a; c
W Oi
3> W
l-l ^
CM ><
T—
0
•
o
V
"ij
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T1
1C
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j£
U
if
133
-------
80. T
60.-
UJ
o
UJ
111
DC
0.
UJ
O
(£
UJ
Q_
40.-
20.
0.
S i i
/
^\
\
10.
20. 30. 40. 50.
60.
ABE CYEARSD
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
-------
d)
t? rH
G PJ
T? R
(0
f^ r.O
0
•H G
4-> fO
O -H
0) .0
0 rH D
in o) 2
o> tn
4-) [T
rO C
ru O
1 — -4
_d 0)
F~i Cii
1
1
1
1
C!
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-*->
rH
o'
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Q> 3 (3
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i a m a
2! MJ X
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03 O
G 5?
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(i) D -r4
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t-t oj a;
cu 4-; 43
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S 1J «?
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?", ^J
m
G
0)
B
r-4 t \
*—* ^
U —I 3)
•y s> Cu
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B '_!•
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2^ ^' G
O -H
E~ P
S
W '-t
P D Q)
CP — 1 C
.a ^j -H
~ ra rJ
^-4 ^J
U T D
1! G G
^3 O -H
3 W =3
•3 M rj
•^ i; X
Qj r-J
T3 D C>
S 4-J 13
4-1 -H O
*o r *^ r 4
w "^ . V_»'
C1
U"> •!/
rC E
rH tl
•H S
• H
t>-
in *- o ui =t
I 5 ? " E
i
r- O O O O
O fNI O O O
CN r\l CM (M CN
o o o o o
!~o r— tn cr> n
LO r»«. r^J Zf r—
'Mr- r-
fN r- r~ UO O
c o o r\i o
D CT> 'N O "I
ro r- ^\j T— rxj
">j "0 xO in >o
in X.Q r^ o? o
•r-l -0
rt >i ^=
G rrj i— ( [/}
(T3 -d fT^ f^J -J-5
rH J^ Xj 4-J
-------
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
-------
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
-------
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.
-------
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. -,«,-
-------
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
-------
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
-------
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
-------
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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ledical Association 18: 371-496."
Khalil, H. and Azia, M.A. 1938. Further observations on
the introduction of infection with S._ haejaatobiujB
through the irrigation schemes in Aswan province.
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.
leiper, B.T. 1915. fiejport on the results of the Bilharzia
mission in Egypt, 1915. Part I. Transmission.
-^S-mLB^i 2l the Ro^al Arai 3§dj.cal Corps 25: 1-55
MacDonald, G. 1955. Medical iaf lications of the Volta
Biver project. Transactions^. B2I§I Society of
Medicine and Hygiene J9: 13-27.
HcJunkin, F, E. 1970. lMiSS££iJ13 S.^^LM^ES.§. f°.£ £2Hi£2i 2f
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
sanitary engineering activities in the Lake Nasser
area, June-July 1970. EM/ES/163. Oct 1970.
Hitwally, H. and El-Sharkaw, P. 1970. Methodology and
application of measuring housing conditions for
rural areas in U.A.R. and siiailar developing
countries. Part I, JoMlJl of the E(jjrj3j:i.an Publj.c
SSalill A§§2£iation 45(5) : 420.
flobarkic, E. H. 1975. £ajrouji Control frojecj: for
is^ Egyptian Ministry of Health. Cairo.
169
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Moser,C.A. and Kalton, G. 1972. Survey Mlfe2^§ iB. Social
l51^1i3Sii25* New York: Basic Books,
Inc. Publishers. p. 467.
Sagaty, H. F. and Bifaat, M.A. 1957. A parasitological
survey of the Kharga and Dakhla Oases in 1952 and of
the Kakhla Oases in 1955. Journal of the E£y_Etian
Association ^Q: 444.
Nooman, Z.M.; Nafeh, M.A.; El-Kateb, H. ; Atta, S. M, ; and
Ezzat, E. S. 1974. Hepatosplenic disease caused by
haeaatgbium in Opper Egypt. Journal of
lSine and Hjcjiene 2Z(2): 42-48.
Cbeng, I.E. 1975. Health problems of the Volta Lake
Eco system. In Man-aadg l-aJS^s a§d Human Heal_th,
ed. Stanley, M.F. and Alters, M.P. London: Acadenic
Press, pp. 221-232.
Goran, A.R.,; Kholy, A.M.; and El-Sayedali,
J. 1962. Epidemiological basis of research in
bilharziasis in Egypt. PjE2S§§3incj of_ In t e rn at_ io nal
S y jf o si o ja on I i_lhar ziasi s , Part I. pp. 183-210.
____ .1966. Impact of econoaic development on health
patterns in Egypt. Ar£kiiSs of Environmental Health
13: 117-124.
__ . 1973. Iai£ti PoMi^lASS JBISki^Is and
Chapel Hill, North Carolina: Carolina Population
Center, University of North Carolina at Chapel Hill,
Eifaat, M.A. 1964. A parasitological survey in Mersa-
Matruah Governient UAR. JSiJIS^i 2f the !s.yjiti,§n
Public Health Association 39 (1): 497
Sifaat, M.A. and Nagaty, H.F. 1970. A survey of parasitic
infections including malaria and nutritional
diseases in Nubia before the construction of the
high Aswan Dam. Ain Shajs Mgdical jouirnal 21^(2) :
155.
Fifaat, M.A,; Salen, S.A. ; and Horsy, T.A. 1963.
Parasitological survey in El Haady El Gadeed, U.A.B.
^5UiI33l of ^he Iai£tian PjjbliS Heailb Association
38: 199-202.
Eifaat, M.A,; Salem, S.A.; and Nagaty, H.F. 1964.
Parasitological and serological surveys in Wadi El
Nat rum DAB Journal of J:he E^ygtian P^Mi5 Health
_9 ( 1 ) : 17.
Buffer, M.A. 1910. Note on the presence of Bilharzia
haematobia in Egyptian mummies of the Twentieth
170
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dynasty (1250-1000 B.C.) , British fledrcal Journal Jh
16-25.
Bussell, C.S. and Landsberg, H.fl. 1971. Internal
environnental problems — a taxonomy. Science J72 (25
June): 1307-1314.
Satti, M.H. 1969-1970. La^S Nasser DeX§i2£ient Center
Jfcealth asjaectsl Nov... 1969^Se£t.. 1970^""
Sherif, A.F. 1968. A new trend for controlling
schistosomiasi-s in hyperendemic area at Iflaka
O.A.R. by elimination ot the parasite from man and
vector. Journal of the Ec[j£tj.an Public Health
Association !j_ (1) : 30.
Scott, D. and Chu, K.Y. 1974. project IB 0658
S§search in the gj2idejni.oJ.ocLy, an^
2f cojQtrol of schistosomiasis in
ISJPJEl ofi s ^isi^ fade f_£om th_e
IS SilM 12 i§JS§ JS2§§2S i£ iJSforj Coast
MPD/24.7 »HC unpublished.
Scott, J.A. 1937. The incidence and distribution of the
husean schistosoffliasis in Egypt. AmSf-iciS J2J!r.Iia.;L of
Hygiene 21: 566-614.
____ . 1969. Schistosomiasis control in water supply
sources. Journal of: the lJ§rj.can Jiat.er Works
Association" 6J ; 352-354.
Shindy, Baligh. 1977, Personal coamunication, Egyptian
Ministry of Agriculture, Cairo.
Sterling. C. 1972. Superdams: the perils of progress.
Boston: The Atlantic Monthly
Coj^ajijr. April, pp. 35-41.
Tuli, R.L. 1966. Report on a ilHO mission for public health
aspects of lake Nasser development. CPD/67,3.
van der Schalie, H. 1960. Egypt's new daa--asset or
liability? Ihe Biologist. 42: 63-70.
____ . 1963. People and their snail borne diseases.
£uacterly. Review 2: 2,106-114.
1972. World Health Organization Project Egypt-10: A
case history of a schistosomiasis control project.
In Tjie Careless TecJinjolo^^ » e^. H. T. Faruar and
J.P. Milton. Garden City, New York: The Natural
History Press.
1974. Aswan Dam Revisited. lUlironmerit 16(9):
171
-------
18-20, 25-26.
Saddy, B.B. 1975. Sesearch into the health problems of
mannade lakes, with special reference to Africa.
Transactions. £0^ Society... Tropical ^§dicine and
6: 39-50.
Barren, K.S. 1975. jSchistosojnijjsisj. se^ec_ted abstracts
J8J_-^9J2^ M.i.T. Press, Cambridge, Massachusetts
and London, England.
barren, K.S. and Mahmoud, A.A, 1975. Algorithms in the
diagnosis and management of exotic diseases
I. Schistosoaiasis. Journal of Infectious Diseases
1JJ (35): 611-620.
Baterbury, J. 1971. ]|an£21§£ §S
-------
of schist os cuiasis. Bulletin o£ the jtorld Health
': 559-566.
Bright, B.H. 1973. Geographical distribution of
schistosoniasis and their intermediate host. In
•52ideiaiol,ocLX and £°Jfi£rol of SchistQsomiasJLS
JSiIliarziasis}_ ' G&- Ansari, N. Baltimore:
University Park Press. pp. 42-U8.
Zaqhloul, A. Z. 1963. Rural health services in
O.A.R. Journal oj the Ejg^£^ian Public HealJLb
Association 38: 217-242.
Zawahry, U.K. 1962, Bilharzia in Children 0-12.
Proceed ings 1st ifiternational Symposium on
Part I. pp. lh 1-228."
___ . 1961. A health survey in Egyptian Nubia. Journal of
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
-------
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
-------
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
-------
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
-------
Latrine
present
cover
date of installation
type
184
-------
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
-------
10* Terrain—elevation from sea level, etc.
11. Agricultural practices and general economy
186
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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
-------
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.
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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.
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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.
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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.
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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
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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.
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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)
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