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EPA 1983 PORTLAND GIARDIA CONFERENCE
NOVEMBER 14, 15 and 16, 1983
REPORT
120" A,
• .s , w ^
•.O:1 n M J s> J i ¦'
Project Officers:
Martha Miller
US Environmental Protection
Agency M/S 313
1200 Sixth Avenue
Seattle, Washington 98181
Jean Knight
Mike Gearheard
EPA Oregon Operations Office
522 SW Fifth Avenue
Portland, Oregon 97204
US ENVIRONMENTAL PROTECTION AGENCY
us. EPA UBRMY REGION 10IMTERMLS
IIIIIIIIIIIII
RXD000020b7
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CONTENTS
PACE
Introduction and Acknowledgements 1
Opening Remarks 2
Giardia lamb11a and Giardiasis 4
Giardia, the Organism 4
Giardiasis, the Illness 8
Testing for Giardia in Water 14
Methods of Testing for Giardia in Water 14
Workgroup Reports: Testing for Giardia in Water 17
Waterborne Giardiasis and its Epidemiology 24
Waterborne Giardiasis 24
Case Study: Giardia and Giardiasis in Washington State 26
Workgroup Report: Surveillance for Waterborne Giardiasis 27
Water-System Evaluation and Control Measures 30
Giardia Control Measures for Water Systems 30
Operation and Maintenance Problems Implicated in
Giardiasis Outbreaks 37
Colorado Case Study 41
Workgroup Report: Water-System Evaluation/Risk Evaluation 46
Workgroup Reports: Control Measures for Giardia
in Water Systems 49
The Future: Regulatory Requirements and Research Needs 53
Workgroup Reports: Future Regulatory Requirements 53
Workgroup Reports: Future Research Needs 57
Informing People about Giardia Issues 59
Public Information 59
Communicating about Giardia-Related Issues among
Concerned Parties 62
Financing for Water-System Improvements 63
Glossary 65
Appendi ces
A: List of Conference Attendees A1
B: Giardiasis, the Illness B1
C: Concentrating, Processing, Detecting and Identifying
Giardia Cysts in Water CI
D: Giardiasis in Washington State;
Giardia Prevalence in Commercially Trapped Mammals D1
E: Public Information El
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INTRODUCTION AND ACKNOWLEDGEMENTS
The 1983 Portland Giardia Conference was held on November 14, 15 and 16
in Portland, Oregon. National experts on Giardia and giardiasis were
invited, as well as state and local water officials and purveyors. The
people attending had two roles: to hear presentations and to work together
as contributing experts in small groups on Giardia-related topics.
The topics were as follows:
Public Information
Testing for Giardia in Water
Financing for Water-System
Improvements
Water-System Evaluation/ Risk
Evaluation
Control Measures for Giardia
in Water Systems
Surveillance for Waterborne Giardiasis
Future Regulatory Requirements
Future Research Needs
We couldn't have put on this conference without the valuable help of
many people. Specifically, I would like to thank the members of the Conference
Steering Committee: Larry Foster, Mark Knudsen, Larry Eisele, John Stoner
and Jim Boydston; and the expert speakers Charles Hibler, Dennis Juranek,
Larry Foster, Byron Plan, Floyd Frost, Ed Lippy, John Kirner, Rick Karlin,
and Jay Vasconcelos. Larry Foster, Byron Plan and Rick Karlin also deserve
special thanks for their assistance with the agenda and throughout the
conference. Finally, I wish to acknowledge the contribution of Jean Knight,
formerly of the EPA's Oregon Operations Office. Her tireless work brought
the conference to reality.
The following pages provide summaries of the information presented by the
speakers and generated by the work groups. Each is given as a short report,
a few with added appendices.
We were very pleased with the discussion and free exchange of ideas that
took place in the conference. The group reports and other products of
the conference will prove useful in the continuing effort to ensure safe
drinking water in Oregon. We present this information in the hope that it
will prompt further discussion, research, experimentation and perhaps more
answers. Please feel free to contact us if you have comments or questions,
and to reproduce this book (or parts of it) and pass it on to others.
Mike Gearheard
Oregon Operations Office
Environmental Protection Agency
555 SW Fifth Avenue
Portland, Oregon 97204 C1
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OPENING REMARKS
The conMe.nee began with a welcome by John \/t
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OPENING REMARKS (Continued...)
Management," only it usually happens after the cases occur. We also find varying
professional opinions about cause, effect and cure -- and about the degree of
"proof" required in the minds of agencies and water-systems operators. (Some of
this is simply difference of professional opinion, occasionally even based on
the same facts.)
This does not mean that giardiasis problems are not addressed. They are. Our
few confirmed Giardia outbreaks have been resolved; through cooperation,
good communication, and (to a certain extent) crisis management. There have been
"boil-water" advisories, increased chlorine requirements, lengthened contact
times, alternate-source development, and in some cases, a "wait 'til it passes"
approach.
But most of our solutions have been a matter of consensus-building after the
outbreak. Under Theory 0, the degree of success we have in dealing with Giardia
depends on consensus-building once in the field. While that's possible, it's
also difficult. We are convinced that consensus-building before an outbreak is
the key to improved Giardia response.
That's the purpose of this workshop. Despite the fact that a lot about Giardia
and waterbome giardiasis is still unknown, our principal interest here is to
examine what we do know, and to come to some agreement about it. Consensus on
various Giardia-related issues will help us all when facing day-to-day Giardia-
related decisions, be they evaluating giardiasis risk, monitoring for its potential
or its occurrence, defining outbreaks at early stages, dealing with it in the
short and long run, or preventing it via treatment.
Most of what we need to know has a spokesperson in this room. Each of you
brings a particular expertise, perspective, and interest to this conference.
Among your experiences are the essential elements necessary for consensus about
Giardia and its management. We need this information to improve our present
approach, and to reduce giardiasis occurrence in Oregon and elsewhere.
Since the knowledge is already here, the challenge is to identify the elements
of what we know about Giardia and to reach consensus. I guess that's why it's
called a workshop: everyone works. The seminar is organized to accomplish
these objectives through small-group sessions and expert presentations.
Giardia is a vital issue for us in Oregon. (I suspect it is for you too, since
beavers don't recognize state boundaries.) We look forward to your input. We
also hope you will leave with more than what you bring: that this experience
will provide some additional worthwhile information for you to apply to your own
programs.
Thank you again for your help. I wish you a productive, enjoyable workshop.
3)
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GIARDIA LAMBLIA AND GIARDIASIS
Vha . Chuck H-tbZe/L and LoJOiy FoAt&n. gave pfiet>entation& on Jwo a^pecti o<5
G-Lasidia. FoZlow-ing an.a 4u.mmcvu.e4 theJji pn.eA entationi,.
Giardia, the Organism (Charles Hiber, D.V.M., Ph.D. Wild Animal Disease
Center, Colorado State University]
Species of Giardia are protozoan parasites found commonly in many
animals, and those reported and described from each animal have been assigned
appropriate names (e.g., Giardia lamblia from man, G. canis from the dog,
G. cati from the cat, and G. bovis from~cattle, to name a few). However,
Filice (1952) undertook a detailed study of the species reported from various
animals and concluded that only two species exist. Giardia muris with
rounded median bodies occurs in mice, rats and hamsters, while G. Duodenalis
(the type species from the rabbit) with claw-shaped median bodies occurs in
many animals, including various species of rodents, ruminants, carnivores,
primates and man. Filice also discovered that only a limited number of
acceptable cross-transmission studies had been performed. Consequently, we
are aware that many species of animals are infected, but we do not know
the host range or host specificity of the organisms.
Giardia leaves the host in a cyst form, a more-or-less resistant stage. This
cyst is oval, and measures 7-8 x 10-12 microns. Within the cyst, the
infective organism contains four nuclei, four median rods referred to as
axostyles, and two median bodies that are claw-shaped in the G. duodenalis
type, rounded in the G. muris type. This cyst is immediately infective upon
discharge from an animal. When ingested by a susceptible host, the cyst is
activated in the stomach and the organism released in the small intestine.
This infective form divides immediately by binary fission to form two vegeta-
tive forms or trophozoites. All multiplication occurs by binary fission.
The trophozoite is pear-shaped, measuring approximately IS x 20 microns. It
possesses four pairs of flagella and a ventral sucking disc, giving the
appearance of a partially scooped-out pear. Internally, the trophozoite
possesses two nuclei, two axostyles and two median bodies.
Animal surveys have shown that a number of wild and domestic animal species
are infected with Giardia. Our data, together with information found in
other surveys, indicates that up to 511 of the beaver and 80-901 of the
muskrat are shedding cysts in the late summer and fall months. We have
found cysts in cattle (about 10%), domestic sheep (about 4%), captive moose
calves (5 of 6) and captive mule deer fawns (about 15 fawns). We have also
found cysts in coyotes, feral dogs and cats and in human stool specimens
from campsites. Although we have not found Giardia in the various small wild
rodents that abound around streams, other investigators have reported a
high percentage infected. We did not find Giardia in any of about 150 horses
(4
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GIARDIA LAMBLIA AND GIARDIASIS
Giardia, the Organism (Continued...)
drinking water from infected streams, but it has been found in one horse in
Lolo National Forest, Montana (verified by CPU). We have not found Giardia
in free-ranging elk, mule deer, bighorn sheep and pronghorn antelope, or
foxes, badgers, skunks, etc.
We examine several thousand dog and cat stools annually at the Veterinary
Diagnostic Laboratory. We find that approximately 20-25% of all dogs and 2%
of all cats (routine stool examination) are clinically infected with Giardia.
If the animal (dog ) presents with diarrhea, and is less than 6 months of age,
851 of the time the cause is Giardia. Postmortem examination of dogs through
the necropsy laboratory has shown that about 90% of the dogs are carrying
Giardia but are not passing cysts, at least in numbers sufficient for routine
recovery.
We do not know the role of the wild and domestic ruminants, carnivores,
and most rodents, as reservoirs for Giardia and as potential causes of
waterborne giardiasis among backpackers, hikers and in municipalities. The
beaver and (possibly) the muskrat, because of the habits, habitat, and the
high percentage infected are the most logical reservoirs for a continuous
source of the large numbers of cysts necessary for an outbreak. Regrettably,
no cross-transmission experiments have been performed to determine if muskrat-
source Giardia are infective for man.
Most of the cross-transmission studies on host specificity of Giardia were
performed at Colorado State University. In summary, we have shown that the
Giardia species found in man is infective for dogs, cats, beaver, pronghorn
antelope, bighorn sheep and various laboratory rodents. We have also shown
that Giardia from dogs, beaver and mule deer is infective for man. We have
been unable to infect cattle, elk, and domestic sheep with Giardia from humans,
but we feel that these failures were logistical in nature (these ruminants were
not thirsty when orally exposed). We had variable success with many of the
above animals, some of which possibly can be attributed to the previous immunity,
concurrent infection with other flagellates (Trichomonas muris), uninfective
cysts, age, diet, etc. Moreover, we often had limited numbers of known
negative animals available for trials. Much more host specificity research
needs to be done,especially with the small rodents that have an aquatic habitat,
and especially with muskrat because they are so ubiquitously infected and
so common on watersheds.
Q. "Which of these animal species do you think have been inadequately sampled
to really come to any conclusions - wild animal samples that is?"
A. "I think that many animals have been inadequately sampled in the West."
5)
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CIARMA 1J\MBLIA AND GIARDIASIS
Giardia. the Organism (Continued...)
Q. "What kind of samples are you talking about? Are you talking about just
going out and picking up droppings?"
A. "No. We do a lot of post morten^as I said; we do about 500 post mortems
a year, on many of these animals. We get in an animal and I have to be there
anyway, so some of my students are always on hand to do a direct smear on
the small intestine. I might add that we have found it recently in six
of seven black-crowned night-herons passing through Ft. Collins. They had
more Giardia than I have seen in anything other than moose calves. The
moose calves we saw were captive at Syville, Wyoming. They were on a
stream, on which there were infected beaver. Five of the six moose calves
had tremendous numbers of cysts in the feces. They were stacked five deep
on a cover slip. Most of the calves were showing very severe clinical
giardiasis. Probably they were compromised because they were raised in
captivity and their thymus gland was not as functional as it should have
been."
Q. "Do you know if anyone has tried to infect the muskrat with human Giardia?"
A. "We would like to do so. We have had a study underway. Thus far, we have
not found a muskrat we are confident has never been infected,or is not
infected and is in the carrier state. So far as I know, no one has tried it.
We are reluctant right now because every muskrat we have examined is
infected, 801 to 901 infection. Of those that are in the negative category,
post mortem analysis was such that we couldn't say for sure. We did call
them negative, since we couldn't find the organism. I feel, to follow Dr.
Meyer's question, that the muskrat may be far more important than we have
cons idered previously."
Q. "Have you done any work, or is there any information available on rodents
as carriers, and has the field mice population been evaluated?"
A. "Of those we looked at in Colorado, and we have looked at a tremendous number
of these little rodents, we have yet to find a single Giardia cyst.
However, the material I have from Lolo National Forest (I think about
20 samples) three were infected, and two I could recognize as the Giardia
muris-type organism. The muskrat samples that we get from Lolo do have
the Giardia lamblia- type organism."
Q. "You have oppossums in Colorado?"
A. "No."
Q. "You mentioned that there was kind of a seasonal trend in terms of the
infection rate. How many years did you look at those figures?"
A. "Three years."
(6
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GIARDIA LAMBLIA AND GIARDIASIS
Giardia, the Organism (Continued...)
Q. "Regarding beavers, this trend of stool/pond activity sounds plausible with
all tourists. I was wondering if you looked at the natural history of
the organism in the beaver itself: whether the beaver that gets infected
this summer is going to have it next summer?"
A. "No, we haven't. It's difficult to trap and tag a beaver with all the
beaver-trapping activity going on in Colorado."
7)
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GIARDIA LAMBLIA AND GIARDIASIS
Giardiasis, the Illness (Larry Foster, M.D., Oregon State
Health Division, Portland, Oregon)
The aha/iti, Lowiy fie-^eju to ajie. Zn the body ol ku> outLLne., pAe-iented -in
Appendix B .
We may see a range of clinical pictures with giardiasis. At the top of the list
is asymptomatic infection: I think this is important for all of us to consider
because of the potential public-health importance of the asymptomatic infection,
particularly in the day-care setting. The literature has not described
satisfactorily the natural history of asymptomatic infection in humans.
In earlier experiments, a group of 14 people were followed after experimental
infection. All of them cleared their parasites within 41 days. Some of them
had a symptomatic illness, and some didn't. If we were to judge from these
limited observations, it would seem that the asymptomatic infected state persists
for a relatively short period of time. Yet anecdotal evidence we collect
monthly from day-care centers here in Oregon and elsewhere certainly suggests
that the asymptomatic infected state persists for a very long time. I think
this is an area in which we need a great deal of study, particularly to help
us judge what to do to prevent giardiasis transmission in day-care-center
settings.
Next, after asymptomatic infection, is acute clinical illness: the textbook
description of giardiasis. Certainly some patients do have the classical
presentation, which is: sudden onset of explosive diarrhea which is foul
smelling, very little blood or mucous in the stool, a lot of bloating, a lot
of gas, and a lot of cramping. Patients with just diarrhea could mimic a
diarrheal illness caused by one of many other organisms -- bacteria, parasites,
viruses.
The duration of the illness also needs further study. For a case definition
in Oregon epidemiological studies, we have recognized the classic symptoms of
explosive diarrhea, bloating and cramping. Clearly, we have missed some
cases that way because even the literature has reported confirmed cases in
people who were ill only three or four days. Long duration of symptoms at
least does help us to distinguish giardiasis cases from some other diarrheal
illness.
(8
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GIARDIA LAMBLIA AND GIARDIASIS
Giardiasis, the Illness (Continued...)
Another interesting area in the study of giardiasis is that of the chronic
occurrence of symptoms in the person infected with Giardia. The symptoms are
variable in these people, but usually they have intermittent diarrhea and the
bloating and cramping. Often, the illness is serious enough to lead to weight
loss over a period of months. You hear about people who say, "I've been
having this diarrhea off and on for the last seven or eight months, and I've
lost 30 pounds." Additionally, a chronic syndrome of intermittent diarrhea
has been reported in as many as 10% of people who have been treated for
giardiasis and who have apparently cleared the parasite. Some folks have called
it the "post-giardiasis syndrome." I'm not sure we fully understand the
mechanism of this.
The diagnosis of giardiasis is a very special problem to us that have to deal
with epidemic investigations and clinical situations day-to-day, because it
is neither easy to do nor cheap. The most frequently used method, of course,
is the microscopic examination of the stool, usually using a formalin-preserved
stool. This enables us only to identify the cysts. It isn't a 100% method:
one study, for example, has said that a single stool specimen, carefully
examined, will identify only 76% of people who have giardiasis. A second
specimen increased the percentage to 90%, and a third up to around 97%. Other
research backed up these figures. So if we are really going after the
diagnosis of giardiasis in an individual, we should use three stool specimens.
We routinely recommend this, with each specimen to be collected at least 24
hours apart. In the private laboratory here in Oregon, a single stool
examination may run $30 to $40, so we are lucky to get even one sample.
Q. "You said collect one stool specimen each 24 hours. Doesn't some of the
literature say to leave one to three days between specimens?"
A. "Well, the 24-hour timing is what we consider a balance. That covers
72 hours. We recognize the problem of intermittent shedding, although
we don't yet fully understand what to expect in terms of shedding in various
stages of clinical illness. We definitely think it is important that all
the stools not be taken in one day because of the intermittent shedding.
Of course, when we have a person with acute, explosive diarrhea and who is
miserable, we want to make a diagnosis as fast as we can. The 24-hour
spacing is therefore the compromise we have come to. I'd be eager to hear
what folks from the other states do."
PVA or polyvinyl alcohol is the preservative we use for samples from patients
who are in the acute phase of illness and we can't find cysts. As I mentioned,
formalin won't preserve the trophozoite, but PVA will. It enables us to
identify the person excreting mostly or exclusively the trophozoite. A lot
of textbooks talk about warm, fresh stools to identify the trophozoite: I think
this is a figment of the authors' imaginations. Except for hospitalized patients,
have you ever tried to get to the laboratory a fresh, warm stool from a patient
who is at home twenty miles away? Of course, in the ideal setting of a
hospitalized patient, or the patient who has a bout of diarrhea while at the
office, it is possible.
9)
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GIARDIA LAMBLIA AND GIARDIASIS
Giardiasis, the Illness (Continued...)
Another promising test that a lot of doctors use now is the string test. The
person swallows a gelatin capsule attached to a string. The string is left in
for a period of time, then withdrawn. The mucous and material adhering to the
string can then be examined for the presence of the organism.
Aspiration of duodenal contents or biopsy aren't done much anymore because
stool examination and/or the string test are much less invasive and less
expensive.
In respect to the pitfalls of diagnosis, we have already talked about the
intermittent shedding problem. I think we should also consider causes of
falsely negative stool examination tests for giardiasis. Many things
used in the management of diarrheal patients interfere with identification of
the organism on the microscopic slide. For example, it isn't unusual for a
giardiasis patient to show up having been worked up with a barium enema before
the doctor even thought of doing a stool examination for Ciardia. The barium
can interfere with seeing the organism. Some antibiotics, antacids, anti-diarrheal
medications, laxatives, and enema preparations can interfere with the test.
Because of this, one should consider the possibility of parasitic infection
early in the patient's workup. If you get a negative test on a patient who
appears to have giardiasis, be sure to consider that other factors might
cause a false negative on a stool examination.
Hie small table listed under "Treatment" in (Appendix B) is from the
Medical Letter. These are the standard treatments used by most physicians in
Oregon. I would be interested to hear whether other states follow along with
the Medical Letter. I just want to make a few brief comments about each drug.
Quinacrine is probably the most effective of the drugs. Effectiveness rates
have been quoted to be around 95% among adults. It's important to note a
recent study with children, however: those under age 5 had only a 64%
effectiveness rate for eradicating the organism in one course of treatment,
compared to 92% in older children. This probably has to do with the bitter
taste of the medicine causing non-compliance. It also might have to do with
the side-effect of vomiting, which seems to be fairly common in younger kids.
In Oregon, we don't really encourage using Quinacrine for younger children,
because we don't believe you can get it down and keep it down.
Metronidazole or FlagylR is also pretty effective. Effectiveness rates in
adults for the standard regimen have been quoted from 891 to 1001 in most
studies. Single-dose Flagyl^has been considered. One study using 2.4 grams
found only a 50% rate, though. I think it's important to note that Metronidazole
is not approved by the FDA for treatment of giardiasis because of concerns about
teratogenicity in laboratory animals and mutagenicity in bacteria. So, even
though Flagyl^ is probably the more commonly used drug for giardiasis here
in Oregon, it isn't approved for that purpose by the FDA.
(10
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GIARDIA LAMBLIA AND GIARDIASIS
Giardiasis, the Illness (Continued...)
Furazolidone is the third drug that we have available. This is what we generally
recommend for children because it is available in a syrup as well as a tablet.
Kids tolerate it better for its taste. You'll note the Medical Letter recom-
mendation describes a seven-day regimen. A study published earlier this year
compared a 5-day regimen of furazolidone or FuroxoneR to a 10-day regimen.
The effectiveness of the 5-day regimen was only 20%, and that of the 10-day
regimen was 921. We strongly advocate the longer regimen because we've had
some experiences with treatment failures in pre-school children.
Another drug that is occasionally mentioned is paromomycin, sometimes
suggested for treatment of severely symptomatic giardiasis in pregnancies,
as it is minimally absorbed from the intestinal tract. I don't believe any
extensive clinical trials have been done with it.
We need to consider reinfection versus compliance with the recommended
treatment when we judge whether people are truly treatment failures, and
when deciding how to further manage a patient who continues to be symptomatic
or continues to excrete Giardia after a course of treatment.
Next, I wish to review the basic modes of transmission for giardiasis. The
first, and in my mind, foremost is day-care transmission. I think the better
way to say that is "transmission among pre-school children," particularly those
that are still in diapers. Hie Washington survey found over 1% of children
ages 1 to 3 to be excreting Giardia Iambiia. In South Carolina, a study
of rural white first-graders found that among those who had been
attending day care, 18.8% were excreting organisms. Only 2.8% of those who
had not been in day care were excreting the organism. We are finding here
in Oregon that day-care outbreaks pose special problems because of "treatment
failures." We're dealing with reinfection, expense, risk of medicating pre-
school children to control a minimal illness. Lots of judgements have to
be made in coming years in making decisions about controlling Giardia in day-
care centers.
Household-contact exposure probably does account for transmission, particularly
among pre-school children and from them to adults in the family. Sexual
contact, particularly among gay men, is becoming a recognized mode of transmission.
I won't discuss waterborne transmission, since there will be a session on it
later.
I'm aware of only one outbreak of foodborne giardiasis in the literature. It
was a situation in which a grandmother changed here grandson's diapers, then
took some salmon out of jars and arranged it for her husband to take to work
to serve his co-workers. Many of his co-workers developed diarrhea, and were
diagnosed to have giardiasis. The grandson was later diagnosed to have probably
caused this outbreak. I suspect foodborne giardiasis occurs more often than
we recognize it.
11)
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GIARDIA LAMBLIA AND GIARDIASIS
Giardia, the Illness (Continued...)
Q. "Do you have any comments on the reliability of the string test?"
A. (Dr. Juranek:) "I can't quote the literature off the top of my head, but
they did do a recent comparison of the string test and stool exam on
several patients, and the string test was apparently a little more
sensitive."
Q. "Do you know what the cost would be for getting the analysis done?"
A. "I think the lab cost would be as much per test as the stool specimen exam.
There would be more cost, of course, for the doctor to administer the string
test."
Q. "Cryptosporidia is a protozoan that has been suggested to be perhaps even
more common than Giardia, and capable of causing human intestinal disease
with symptoms resembling Giardia."
A. "That is a really timely comment. .Not much has been said about cryptospor-
idiosis up to this point, and yet right here in Oregon we now have a cluster
of cases that look clinically like giardiasis. I think cryptosporidiosis is
a diagnosis we need very much to consider and study to see how commonly it
occurs here."
Q. "It seems particularly likely that it is occurring because the organism,
like Giardia, is prevalent in wild and domestic animals. There is also no
reason it can't be waterborne, just like Giardia. So you may have it as
a component at some outbreaks where you can't find Giardia in the water.
Up to now, nobody's taken a hard look at these unusual organisms."
A. "It does take special techniques to identify Cryptosporidium in the lab,
and that's why we may be missing it in some of these Oregon outbreaks."
Q. "What about animal-to-person transmission, such as from a domestic pet?"
A. "I think that's really important. In fact, in most of our giardiasis
cases we don't really identify a common source for an outbreak. There must
be a fair amount of person-to-person transmission within households or
other group settings, and perhaps by contact with infected animals, domestic
or otherwise."
Q. (Inaudible)
A. "Oregon Administration rules require the Oregon physician or other health-
care provider to report to the local health department that a giardiasis case
has occurred. The local health department does an investigation looking for
possible sources of exposure that might have public-health importance. Then
(12
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GIARDIA LAMBIJA AND GIARDIASIS
Giardia, the Illness (Continued...)
it reports the results of the investigation to the State Health Division. It's
only when either the county health department or the State Health Division
thinks there may be a cluster of cases with a water system as the source
that we do anything about the water system. In that instance, our first
step would be to review the water system's records. What do we know about
its treatment system? What do we know of its bacteriological history? The
second step would be to notify drinking-water program staff, who notify the
water purveyor. In cooperation with the EPA, they would get some bacterio-
logical tests, do a sanitary survey, and work with the purveyor. We
wouldn't notify the purveyor of an individual case of giardiasis in the
community served by his or her water system. Otherwise the purveyor would
be getting notified all the time, of cases that have nothing to do with the
water system."
13)
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TESTING TOR GIARDTA IN WAITER
To bug-in the u)oA.kgsiou.p talk.
Methods of Testing for Giardia in Water (George (Jay) Vasconcelos, Regional
Microbiologist, Region 10 Laboratory,
Manchester, Washington)
Background:
Although recent development of an excystation technique by Drs. Bingham,
Meyer, Rice and Schaefer could in future lead to developing cultural methods,
at this time no reliable methods exist for culturing Giardia cysts from water
samples. At present, the only practical method for determining the presence
of cysts in water is by direct microscopic examination of sample concentrates.
Microscopic detection in water-sanple concentrates isn't an ideal process.
Finding and identifying the cysts relies almost entirely on the training,
skill, experience and persistence of the examiner. (And it is a skill not
widespread among water-supply laboratories.) But despite its limitations,
microscopic identification is currently the best method we have.
Years ago, the basic assumption was made that in order to find Giardia cysts
in water, some form of sample concentration was necessary. As early as 1956,
labs were using membrane filters with a porosity of 0.45 ^im. With few exceptions,
these attempts were unsuccessful. The center for Disease Control has tried
particulate filtration, with diatomaceous earth as the medium. This removed
the cysts from the water, but the cysts couldn't be separated from the
particles of diatomaceous earth.
With the recent increase in the incidence of waterborne giardiasis, further
efforts have been made to improve the detection method. An ideal method would
be one that recovers all cysts in a water sample rapidly, cheaply and simply;
allows rapid detection, identification and quantification; and provides
information on the viability of and/or infectivity potential of cysts detected.
Unfortunately, no such method exists. The methods presently available
can be broadly separated into two general stages: primary concentration and
processing (see Table 1 on next page), and detection and identification
(see Table 2 on next page).
(14
-------
TESTING FOR GIARDIA IN WATER
Methods of Testing for Giardia in Water (Continued...)
TABLE 1: PRIMARY CONCENTRATION AND PROCESSING METHODS
HETHOQ
1. Membrane Filtration
CelIulosic
(47mm-0.45umJ
Polycarblnate
(293rait-5um)
2. Particulate Filtration
(diatomaceous earth, sand,
etc.)
3. Algae (Foerst) Centrifuge
4. Anionic and Catlonic
Exchange Resins
5. Epoxy-Fiberglass Balston
Tube Filters
(10"-8um)
INVESTIGATOR (S)
Chang & Kabler
USPHS, 1956
Pyper, DuFrain & Henry Eng
1982, (unpublished)
Shaw et a1_, 1977
Juranek, 1979
Holroan et aj_, 1983
DHHS, Washington
Brewer, Wright State UN.
(unpublished)
Riggs, CDHS Lab, Berkley, CA
(unpublished)
6. Microporous Yarnwoven Depth. Jakubowskl, Erlckson, 1979 6
Filters
(7 A lum orlon & polyprolylene)
7. PelUcan Cassette System
1980, EPA-C i nc1nnat t
8. Fi1terwashing Apparatus
Millipore Corp.
(unpublished)
DuWalle, U. of Wash., 19B2
(unpublished)
RESULTS
Generally unsucessful
Passing 1 gal/min (J
10 PSI. 15-1800 gal
total.
Generally good removal
but poor eluation
Good rapid recovery,
but 1 united in field
use.
Generally unsucessful
Overall recovery 20-801
Recovery 3-151
Extraction ave. 58%
May be useful for
processing filter
washings
Claims 751 recovery
from orlon filters
TABLE 2; DETECTION METHODS
METHOD
INVESTIGATORS(S)
RESULTS
1. Immunofluorescen
__
Riggs, C50HS Lab, Berkley, CA
1983
Good prep., Cross Rx
1FA
Monoclonal Antibodies
Sauch, EPA-C1nc1nnatl
Riggs, CSDS
Riggs, CSOHS
Sauch, EPA-C1nc1nnat1
(unpublished)
Still under study
Still under study
15)
2. ElISA Method
3. Brightfield/Phase Contrast
Hungar, J. Hopkins MD, 1983
EPA Consensus method
Feces samples only
Ongoing
-------
TESTING FOR GIARDIA IN WATER
Methods of Testing for Giardia in Water (Continued...)
Copies of Table 1 and Table 2 are also shown in Appendix C, along with
further detail about the methods.
EPA Consensus Method:
In September, 1980, the EPA convened a workshop on Giardia methodology in
Cincinnati. Its main purpose was to identify the best available methodology,
and to agree on a reference method. The five labs in attendance recognized
that any proposed method would be based in large part on opinions and personal
preferences rather than on hard data, but that agreeing on a consensus method
would promote uniformity and provide a basis for future comparisons. Our
lab has modified the EPA consensus method slightly for our use. This method
is outlined below.
Filter unwound into quarters
I
Rinsed in distilled water with polysorbate 20
1
Settled overnight, or centrifuged
*
Collect sediment and add 2% Formaldehyde in PBS
I
Settled overnight, or centrifuged
Collect sediment
"V
4"
>1 g-
I
Sucrose or
Percoll-sucrose
gradient
T
ZnSO/
<1 g-
I
Flotation
Microscopic observation of the entire
concentrate (Brightfield/Phase-contrast)
(16
-------
TESTING FOR GIARDIA IN WATER
The topic, of Workgroups 2, 3a, and 3b was "Testing foA Glxuidia In Wate.fi."
The EPA suggested the. gAoups cUacuss the following questions:
- What do and don't the tests tell you?
- How can testing be used moxe effectively?
The EPA also suggested the following possible final pfioducts •• A List of
InfoAmation that can be gained th/iough Glxuidla tests. Suggestions fofi
koiv and when Glafidla tests can most effectively be used. A description
of needed fieseafich on Glafidla testing.
Testing for Giardia in Water: Report of Workgroup 2
The group discussed general questions surrounding testing for Giardia, but
it was unwilling to go further until the question of whether testing was
even useful was addressed. The question defined was, "Is routine testing
for Giardia cysts in water appropriate?" The group decided that routine
testing was not. Stating the conclusion as a problem gave the following
positive and negative aspects:.
Problem: Routine testing for presence of Giardia cysts in water is
inappropriate.
Positive aspects
of routine testing
It's appropriate in
some circumstances:
it establishes a
baseline of data
it establishes a
historical record
Negative aspects
of routine testing
It's insensitive
The results are not
interpretable
It's sometimes unnecessary
Question exists about
viability of cysts
It's expensive
It's time-consuming
The group then came up with the following strategies to handle the negative
aspects listed above.
- Need to quantify total number to species
- Must improve training of technicians
17)
-------
TESTING FOR GTAKWA IN WATER
Testing for Giardia in Water: Report of Workgroup 2 (Continued...)
Should improve sampling to reduce other organics
Possibly develop specific dye tags/labels for Giardia
Devise trapping techniques with better recovery by the
average lab technician
Finally, the group identified three alternatives to routine testing.
• Evaluate risk in the watershed,
• Evaluate biomass instead of testing routinely, and
• Put effective treatment into place.
(18
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TESTING FOR GIARDIA IN WATER
Testing for Giardia in Water: Report of Workgroup 5a
The group determined the following:
What do tests tell you?
A positive test means that the water contains Giardia
cysts and was fecally contaminated.
- In filtered water, a positive test means there's something
wrong with the filtration.
In untreated water, a positive test means that there may or
may not be infections. Adequate treatment is called for.
What don't tests tell you?
- A test doesn't tell the number or concentration of cysts in the
water. (You can't quantify results by extrapolating the number of
cysts found by a test.) .
- If cysts are found, the test doesn't tell whether they are viable
(dead or alive).
- Test doesn't tell whether cysts in the water are infectious to
humans.
- Test doesn't indicate which species was the carrier.
- A negative test doesn't mean cysts aren't there.
How are tests used most effectively?
- For confirmation in an outbreak.
- To provide guidance for determining the appropriate treatment.
- To establish a data-base showing prevalence of positive Giardia
tests.
Research still needed:
- How often should people sample?
- How long should they sample?
19)
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TESTING FOR GIARDIA IN WATER
Testing for Giardia in Water: Report of Workgroup 3a (Continued...)
- Improved methods for detecting Giardia cysts in water:
a) Better method for isolating cysts
b) Better method for detecting cysts during test
- Determine proper holding time and transit conditions.
-------
TESTING FOR GJMIIIA IN WATER
Testing for Giardia in Water: Report of Workgroup 3b
The group began its presentation by saying, "We didn't come up with any
answers, but we did come up with some pretty good questions." The
questions follow.
1. Research needs
a) Need research on removal of cysts from media.
b) Need a less time-consuming technique for testing water for Giardia;
also a less technically difficult method.
c) Need a better device for monitoring treatment efficacy relative to
removing Giardia cysts or other particles/microbes of that size.
Could one use an artificial item similar to a Giardia cyst as a
monitoring device? Need to detennine that technology.
2. Epidemiological observations and questions
a) Need coordination between EPA's surveillance of water systems and
the State's epidemiological surveillance.
b) Has a protocol been developed to implement epidemiological surveillance
throughout the state?
c) We must realize that Giardia is endemic in the population. What is
a baseline of endemic giardiasis?
d) What causes this organism to become a pathogen? (We know asymptomatic
carriers exist.)
e) Cases vs. carriers: why outbreaks? We determined the following
factors could influence the outcome:
Compromised hosts - Is the host stressed for some reason,
such as a previous illness?
- Exposure level (dosage of cysts) may vary.
- The pathogenicity of Giardia subspecies may vary.
f) Can we immunize against giardiasis?
g) We need to determine the importance of waterborne giardiasis relative
to other methods of transmitting it. (For example, how important is
waterborne transmission vs. person-to-person transmission?)
21)
-------
TESTING FOR GIARDIA IN WATER
Testing for Giardia in Water: Report of Workgroup 5b (Continued...)
3. Monitoring for Giardia in water systems
a) Do we need to monitor water systems for Giardia? If so, what type
of water systems need monitoring?
b) It may not be useful to monitor raw or surface water, since all raw
or surface water can potentially contain Giardia.
c) It may be useful to monitor treated water for Giardia to help assess
whether a treatment system is working. For systems with limited
funds and resources, however, is it reasonable to expect treatment-
monitoring for Giardia when the goal is just water quality that
meets EPA standards (1 - S NTl))?
d) If you monitor treated water, find cysts, and the cysts are not
viable, is there a problem? (Perhaps the treatment kills the cysts.)
e) If you have full treatment, (i.e., coagulation, flocculation,
sedimentation and filtration) and Giardia cysts are recovered, is
there a problem with the treatment? Is the problem in the operation
of the plant?
f) Can treatment systems presently in use that are dependent on source
adequately remove viable, infective Giardia cysts - or remove them
in adequate numbers to prevent disease outbreaks? Can we monitor
for this treatment efficacy in some way to provide us with a level
of security?
g) Even if you provide great treatment, it doesn't guarantee that you
will prevent outbreaks, because of cross-connections, new connections,
et al.
h) Can we define a treatment regime to control for Giardia in water that
addresses such variables as chlorine residual, contact times and
turbidity?
4. Miscellaneous observations and questions
a) Politically, one would have to take action if Giardia cysts are
found in finished water.
b) What is the cost effectiveness of doing something to prevent an
outbreak? How safe can we be for the dollars available? What other
factors should be taken into account in assessing the cost of an
outbreak?
(22
-------
TESTING FOR GIARDIA IN WATER
Testing for Giardia in Water: Report of Workgroup 3b (Continued...)
5. Narrowed-down problem
a) Should we determine which systems could be a problem?
b) Are adequate monitoring methods available to monitor domestic water
treatment or to obtain viable, pathogenic cysts where present?- Are
these methods cost-effective?
23)
-------
WATERBORNE GIARDIASIS AND ITS EPIDEMIOLOGY
Pemtca JuAanek, and ByAon Plan and Floyd Fh.ot>t, gave pKunntatiom on
g-laAduuii and i£t> epidemiology. Wosikgioup S dUcui-ied the question oi
-iu/iv&iZCance on. giaA.dia&AJ>.
Waterborne Giardiasis (Dennis Juranek, D.V.M., M.Sc.,
Center for Disease Control,
Atlanta, Georgia)
Table 1 on the following page summarizes selected epidemiologic characteristics
of waterborne outbreaks of giardiasis in the United States. The five outbreaks
included in the table were selected as being representative of the majority
of outbreaks.
Although outbreaks have many similarities, it must be emphasized that no two
outbreaks are exactly the same. Identifying the subtle differences between
outbreaks to try to learn the cause often requires a cooperative effort between
engineers, water-treatment plant operators, health-department personnel, and
epidemiologists. Failure to enlist the assistance of these community,
state or Federal resources can impede confirmation and control of a
waterborne outbreak. It is important to remember that:
1) Not all Giardia outbreaks are caused by contaminated
municipal drinking water.
(The investigator should first rule out exposure to raw stream
water, day-care-center associated infections, homosexual contact,
and travel to Giardia-endemic countries.)
2) Not all waterborne outbreaks of diarrhea are due to Giardia.
(Although when a cause is found, Giardia does head the list of
infectious organisms, in most waterborne outbreaks of diarrheal
disease reported to the CDC, a causitive agent is never found.)
3) Water filtration is thought to provide an effective barrier
against waterborne transmission of Giardia cysts.
Several outbreaks of waterborne giardiasis have occurred on
water systems enploying water filtration as part of the treatment
process. But it must be emphasized that in every instance, there
were either defects in the filters themselves or in the way
they were operated, that caused the filter to be ineffective.
(24
-------
Table 1 (Juranek)
Representative Waterborne Outbreaks of Giardiasis
(Summary of selected epidemiologic variables)
VARIABLE
1974
Rome, NY
Pop. 50,000
1976
Camas, WASH
Pop. 6,000
1977
Berlin, NH
Pop. 15,000
1980
Red Lodge, MT
Pop. 5,000
1982
Reno, NEV
Pop. 140,000
Estimated % of
population infected
Time of year
Type of Water
No. of Surface
Sources.
Origin of surface
water
10.6%
Spring
Surface
1
4%
Spring
Surface & Well*
2 with one water
treatment facility
Mountain mountain stream
streams to
impoundment
reservoir
5%
Spring
15-20%
Early Summer
Surface Surface
2 with 2 water 1
treatment facilities
mountain rivers
mountain
0.1%
Fall
Surface & Well*
1 with 4 water
treatment facilities
mountain river
Water chlorinated
Amounts adequate
for bacterial dis-
infection
YES
NO
YES
YES - but temporary
interruptions
YES YES
YES - all times NO
YES
YES - all times
Water filtration
Type of filter
NO
Giardia cysts
recovered from water
YES
YES
Pressure filter
YES
YES NO
System 1 - pressure
filter
System 2 - Gravity
sand filter
YES NO
YES - in only 1 of
4 treatment plants
Gravity sand filter-
but not in operation
at time of outbreak
YES
H2O contamination
Sewage x-connection NO NO
Human possible unlikely
animal possible likely
NO
possible
poss ible
NO
possible
possible
NO
possible
likely
*Well water not implicated in outbreak
/—\
LO
CM
-------
WATERBORNE GIARDIASIS AND ITS EPIDEMIOLOGY
Giaxdia and Giardiasis in Washington State
(Byron Plan, M.Sc., Floyd Frost, Ph.D.
Department of Social and Health Ser-
vices, Olympia, Washington)
Byron presented the history OjJ the problem, thz 6te.pt, taken to begin a
concerted investigation into thz -cncx.cte.ftce. and extent ofj watzrbomz Giardia.
in Washington, and thz. results paAt o^ the. investigation. Floyd
presented the research iindingt, and dxscusizd their implications in tojute
public health.
Byfion also noted that although the actual project was at an and,
thz good Aurvzillancz procest, established during the research ha& resulted in
their V&paAtme.nt Atill receiving information about human cases, and being
involved in epidemiologic giardia&iA investigations.
Unfortunately, a transcript oft the presentation is not available. Sat the
fioltoiving abstract, plus two articles co-authored by Floyd and Byron that
aAe in Appendix V, cower the -iame topic.
Waterborne Giardiasis in Washington State
A project funded by the Health Effects Research Laboratory of the EPA and by
the Washington State Department of Social and Health Services examined the epi-
demiology of giardiasis in Washington, with special emphasis on waterborne
transmission of the disease.
Four successive seasons of aquatic mammal trapping established that Giardia-
positive animals are distributed widely throughout Washington state.
During the 1977-78 trapping season, 191 of beaver and 43% of muskrat samples
submitted were Giardia-positive. Positive animals were identified in 31 of 39
counties, and in several protected watersheds. Positive animals were trapped
in the 1978-79 and 1979-80 seasons in the Cedar River watershed.
An analysis of human cases followed (between July, 1978 and March, 1980;
excluding migrants, immigrants and non-residents.) It revealed that 44% had
consumed untreated water within two months before onset of symptoms, 18% had
recently traveled to another country, and 701 of infected children had
exposure to a day-care center. (Secondary transmission may account for many of
the 79 clusters of cases observed during the project.)
Outbreaks identified during the period of the project include one among
Boistfort Water System customers. Eleven positive cases were identified during
a five-month period, and a survey revealed that customers had an approximately
20% incidence of giardiasis-like symptoms over the two months. Two control
conmunities surveyed revealed less that SI prevalence. No cysts were recovered
from orlon filter samples of Boistfort water or from beaver stool samples
collected upstream from the intake. After an increase in chlorine residuals,
no new human cases were diagnosed.
-------
WA1ERB0RNE GIARDIASIS AND ITS EPIDEMIOLOGY
Surveillance for Waterborne Giardiasis: Report of Workgroup 8
Workgroup & began with Larry FosteA. des cribing a new pA.ogA.am being put -Into
place -in Oregon: giardiasis reports statewide are going into a central
compu.te.si, with various benefits to result. {Before, Oregon had no statewide
data.-fietrieval system at all.} The EPA provided Group S with the following
questions ••
- Houj can waterborne giardiasis cases be identified?
- Should water systems be surveyed and tested Ion. Giardia
potential.?
- How can depositing oft giardiasis be improved to -identify
connections between water systems and giardiasis? Who
needs to coordinate with whom -in order to make the system
Monk?
- Should Onegon undentake a study like Washington's to
-identify GiaAdia hots pots?
The EPA also suggested the following possible final product: A description
of the necessary activities -in a good surveillance program. [What needs
to be identified? Hou) do you identify it?) Ideas for improving the current
system for identifying waterborne giardiasis. A brief outline of a possible
program for identifying Giardia problem areas in Oregon.
Report of Workgroup 8
The group members found they needed to simplify the problem in order to
deal with questions of surveillance only. They therefore defined the
following arbitrary assumptions (although everyone agreed that all of
these would never happen in real life) simply for the sake of narrowing the issue.
(Inherent assumption:
All surface-water systems are potentially at risk.)
Assumptions:
1. The technology can be put into place.
2. The politics will be favorable.
3. The money will be there.
-------
WATERBORNE GIARDIASIS AND ITS EPIDEMIOLOGY
Surveillance for Waterborae Giardiasis: Report of Workgroup 8 (Continued...)
How do we identify waterborne giardiasis?
1. Get a clustering of cases.
2. Rule out other possibilities for clusters.
3. Do a formal investigation of:
. people cases
the water system
How do we improve identification and reporting?
1. Require reporting on standard form: develop and.implement statewide
training for people to fill out forms.
2. Computerize information, to be able to draw out previously inaccessible
facts and figures.
Who should coordinate the reporting?
The group concluded the state should coordinate the reporting. They sketched
the flow of information as follows:
State
*Si
Water purveyor ^^County^ ^ County
T T
Private Doctors Lab
Should we do a study like Washington?
No; most information would be redundant, and the statewide reporting system
will help identify "hotspots."
What goes into setting up a good surveillance program?
1. A ranking system for those at most risk, to determine where first to
intervene on a limited budget.
(28
-------
WATERBORNE GIARDIASIS AND ITS EPIDEMIOLOGY
Waterbome Giardiasis and its Epidemiology: Report of Workgroup 8 (Continued...)
2. Education of the purveyor (for consistent results) and of operator (for
general good maintenance of systems.)
3. On-site survey of system:
a) Check records,
b) Make tests,
c) Examine site, (etc.)
29)
-------
WATER-SYSTEM EVALUATION AND CONTROL MEASURES
Ed Lippy pie* anted a talk on QontAol Mea6uA&6, and than bant the. following
¦information to -include. In tlvu JiapoKt.
Giardia Control Measures for Water Systems (Edwin C. Lippy, P.E.
Health Effects Research
Laboratory, U.S. EPA
Cincinnati, Ohio)
Figure 1 shows giardiasis outbreaks, distributed geographically. Many water
systems in the northeast and far west use mountain streams as a source of
supply. Because of good-quality water and absence of point-source wastewater
discharges in the watershed, they provide minimal treatment normal chlorination
only. They are required to comply with the National Interim Primary Drinking
Water Regulations which specify microbiological limits for coliform bacteria.
Chlorination provided in these situations is effective in destroying the
coliform organism, but is ineffective in inactivating Giardia cysts.
Figure 2 presents deficiencies in public water systems that cause and contribute
to giardiasis outbreaks. Deficiencies are coded by number in the figure according
to five categories: those that used untreated surface water, those that iised
untreated ground water, those with inadequate or interrupted treatment, those with
deficiencies in their distribution network, and those with problems of
miscellaneous or unknown cause.
The first two categories need no further explanation. Category 3, "Inadequate
or interrupted treatment," is defined as breakdowns or defects in the treatment
process that permit inadequately treated water to be distributed. Category 4,
"Deficient distribution network," includes events that cause contamination
through such problems as cross-connections, ruptured mains or open resources.
Category 5 includes causes not included in the other four categories, or the
outbreak was not investigated enough to determine a cause.
Figure 2's results show that two-thirds of giardiasis outbreaks are caused by
not providing adequate or reliable treatment. Category 3 was further sub-
divided to highlight treatment deficiencies, as shown in Table 1. Chlorination
deficiencies contributed to 28 of the 35 outbreaks, and clarification deficiencies
(coagulation, settling filtration) were responsible for the remaining 7.
The two most common chlorination problems that contribute to outbreaks are: 1)
dependence upon a microbiological standard that does not indicate "safe water,"
and 2) failure to apply currently available technology.
The coliform standard or microbiological contaminant level has been used since
1914, perhaps attaining an unjustified significance. No sound scientific
basis exists for its use as an indicator of safe water. Rather, it indicates
contamination, and should be interpreted accordingly. A positive coliform
sample doesn't mean the water is unsafe to drink. Nor does a negative coliform
sample! A positive sample does mean that coliform bacteria are present. It
may mean that pathogenic or disease-causing bacteria are also present. A
negative sample indicates the absence of coliform bacteria. Pathogens including
parasites, virus and bacteria may still be present. Where water systems may
be challenged by Giardia cysts, reliance should not be placed totally upon
-------
WATER-SYSTEM EVALUATION AND CONTROL MEASURES
Giardia Control Measures for Water Systems (Continued...)
meeting the coliform MCL, but should be placed instead on treatment measures
capable of offsetting the challenge. Minimal chlorination is effective in
destroying coliform bacteria to comply with the MCL, but cysticidal dosing
requires greater amounts of chlorine, and longer contact times.
To effectively inactivate Giardia cysts, chlorination must be practiced
accounting for pH, contact time, temperature and turbidity. Chlorine must
be dosed in response to plant output, and the facilities should be reliable
to the extent that the process is not interrupted.
The pH of the water being chlorinated is extremely important: it determines
the percentage of hypochlorous acid and hypochlorite ion in solution. At low
pH, the hypochlorous acid form predominates. At the higher pH, the hypochlorite
ion is dominant. Hypochlorous acid is about 100 times more efficient in
killing power. (The pH/chlorine relationship is shown in Figure 3.)
Temperature must also be taken into consideration, since chemical reactions
progress more rapidly in warm water. Sufficient contact time is necessary to
allow chlorine to do its job.
The interference of turbidity with chlorination is not as well defined as
the relationships of pH, temperature, and contact time. Interference occurs
when turbidity exerts a chlorine demand. This thereby reduces the chlorine
available to act as a disinfectant or cysticide. Interference also occurs when
particulate matter entraps cysts within the particle structure and shields the
cyst from the disinfectant.
Turbidity has less influence on chlorine demand than was originally thought.
A recent study showed that less than 101 of the chlorine demand was exerted
by particulate matter when the turbidity was at a concentration of less than
20 NTU's. The chlorine demand, amounting to greater than 901, was exerted
by the dissolved and colloidal matter that passed through a 0.45 micron filter.
This should not be used as an excuse for failing to provide filtration where
needed, but should emphasize the need for adequate disinfection as a necessary
treatment step in the multiple-barrier concept.
Reliability in the chlorination process should encompass all factors that
assure continuous, uninterrupted and adequate disinfection. Facilities that
feed chlorine should be able to respond to changes in plant output. The demand
for water in a community fluctuates from highs around 8:00 to 10:00 a.m. and
8:00 p.m., and lows between midnight and 6:00 a.m. Constant-feed chlorinators
paced to dose for an average output will underfeed during peak hours and over-
feed during low-demand hours. (This is especially noticeable during the early
morning hours: people turn on their taps in the morning and get a blast of
chlorine-laden water.)
Reliability in chlorination also requires two cylinders yoked to the chlorinator
so that when one cylinder is empty another can be put in to use without
interrupting feed. Current technology provides for automatic switchover
from the empty to the charged cylinder. Automated monitoring devices are
available to give continuous readout of chlorine residuals. Auxiliary power
should be provided so chlorine feed isn't interrupted by a power failure.
-------
WATER-SYSTEM EVALUATION AND CONTROL MEASURES
Giardia Control Measures for Water Systems (Continued...)
Emergency power generation facilities with automatic start-up are available
and should be incorporated in the chlorination facility.
Control measures implemented during.actual giardiasis outbreaks have been
published, and are listed below.2
Generally, control techniques used in outbreaks consist of immediate steps
taken to control disease, and recommendations for permanent long-term
improvement to the water system. The immediate steps usually improve
chlorination to the extent that a cysticidal dose is applied. The long-term
measures generally require structural improvements, which means 3-5 years'
lead time for design, financing and construction. Therefore, it is important
that the immediate steps taken to control outbreaks are sound and reliable.
1 The relationships between time, water temperature, and chlorine are
demonstrated in the article, "Effect of Chlorine on Giardia lamblia
Cyst Viability," Applied and Environmental Microbiology, February,1981,
pp. 483-487.
2 Control measures have been published in the following articles:
"Tracing a Giardiasis Outbreak at Berlin, New Hampshire," Journal of
American Water Works Association, Vol 70, September, 1978, pp 512-520.
"Waterborne Disease: Occurrence is on the Upswing," Journal of American
Water Works Association, Vol 73, January 1981, pp 57-62.
"The Role of Filtration in Preventing Waterborne Disease, " Journal of
American Water Works Association, Vol 74, December, 1982, pp 649-655.
(32
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WATER-SYSTEM EVALUATION AND CONTROL MEASURES
Giardia Control Measures for Water Systems (Continued...)
Figure 1:
Giardiasis Outbreaks, 1965 to 1982: Geographic Distribution
Outbreaks I I 0
mm 2 to s
33)
-------
WATER SYSTEM EVALUATION AND CONTROL MEASURES
Giardia Control Measures for Water Systems ("Continued...)
Figure 2:
Public Water System-Related Giardiasis Outbreaks, 1965-1982
66.7%
1 - Used untreated surface water
2 - Used untreated ground water
3 - Inadequate or interrupted treatment
L| - Deficient distribution network
5 - Miscellaneous or unknown causes
(34
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WATER-SYSTEM EVALUATION AND CONTROL MEASURES
Glardia Control Measures for Water Systems (Continued...)
Table 1
GIARDIASIS OUTBREAKS
PUBLIC WATER SYSTEMS, 1965-1982
INADEQUATE/INTERRUPTED TREATMENT (#3)
DEFICIENCY
Chlorination (28) Clarification (7)
Inoperative Inadequate Unknown Coagulation Filtration
3 13 m 5 4
Camas Camas
Berlin Berlin
Vail Leavenworth
Estes Park Larimer Co.
(Bypass)
Pagosa Springs
Reno
Florida River
Estates
35)
-------
WATER-SYSTEM EVALUATION AND CONTROL MEASURES
Ciardia Control Measures for Water Systems (Continued...)
Figure 5:
Effect of pH on quantities of hypochlorous acid (H0C1) and hypochlorite
ion (0C1~ ) present in water (Berg, 1966)
50 I
a
o
100
-------
WATER-SYSTEM EVALUATION AND CONTROL MEASURES
Operation arid Maintenance Problems Implicated (John Kimer
in Giardiasis Outbreaks City of Tacoma Water Division
'Facoma, Washington)
Camas and Leavenworth are both cities that have suffered from a waterborne
outbreak of giardiasis. I'd like to talk to you from two standpoints today.
First, what went wrong, and second, a more general basis, what can go wrong, aid
what can we do to keep it from happening?
In evaluating a water system, I think the first two things I'd say is 'survey,
survey.' Know what you've got. If you don't know what you've got., you're never
going to be able to find the source of the problem. Don't just look at the
plans; don't just listen to what the operator tells you. (He probably heard it
from the guy who was the operator before him, and has never bothered to dig all
the way through and follow each line through the plant to see where it goes.)
Try to understand what the source is. Dr. Juranek talked about walking the
supply at Camas yesterday: when he first walked the supply he found
sticks that had gnaw marks on them. This was the first time anybody had
bothered to check out the beavers. In Leavenworth, for another example, we had
two supplies coming into a chlorination system. 148 people fed off a raw water
line. (They should have been goners.) Then it went through a water treatment
plant with a filter bypass plant. This is something to look for if you're
involved in public health inspection of new facilities, a filter bypass plant is
something you always want to try to avoid. (In some situations, the argument
will be, it's absolutely essential for emergencies. Tell them to put it in, but
leave a piece of pipe missing. If they have an emergency they can put the pipe
in, but it's not necessary all the time.) Valves are not adequate protection.
Then, in Leavenworth, water was distributed from the treatment plant to the
reservoirs through pump stations and in some cases through automatic valves,
and others in the well from the other end.
I don't share the total concern over pressure filters that some other engineers
have expressed. The reason I don't share quite that level of concern is I
think there are some small communities working in mountainous terrain where
they may be the best thing you can get.
Most of you are familiar with rapid-sand filters and know that a surface washer
suspended 13 or 9 inches above the media is about as effective as no surface
washer at all. Normally you try to get the surface washer to within a couple
of inches of the media, so when it does clean the system it provides some
break-up of the material that's collected on top of the filter.
When these things are "built," (what putting the media into a filter is called)
they have about 18 inches of anthracite media. A conventional rapid-sand filter,
as constructed today, will almost always have a layer of this anthracite coal
above some silica sand, possibly above some garnet sand. The anthracite coal
is coarse. It's constructed so, in a cross-section, the filter has coarse
material, finer material, finest material. The idea is that you can get longer
filter runs and hold more material in the filters by allowing it to penetrate
-------
WATER-SYSTEM EVALUATION AND CONTROL MEASURES
Operation and Maintenance Problems Implicated
in Giardiasis Outbreaks (Continued...)
this coarse material. In theory, nothing would get through the finest
material. (If particles that you are attempting to remove by filtration
get to the finest material, they will mat out, not penetrate, increase
head loss in the filter, and require a backwash.)
In Camas, we regraded and replaced the filter media. The problems we saw were
definite media loss, primarily in the anthracite: not an unusual occurence.
(Most utilities with rapid-sand filters do replace anthracite media on a regular
basis.) Ilie interesting thing about the Camas operation is that the plant was
built prior to the Safe Drinking Water Act, when the 1962 public health
service standards called turbidity an aesthetic concern rather than a health-
related concern. They built the plant like that just because they didn't
like mud in the water.
The media they put in should have been effective, but the problem is one of
pre-treatment. I don't know how many treatment plants I've looked at over the
years that have had little or no pre-treatment. Pre-treatment can be any
number of chemical additions, depending on the situation you've got. Great
pre-treatment can be the addition of some polyelectrolyte primary coagulant
and a shot of filter aid with ten minutes' detention time before the filter,
or it can be a whole battery of chemicals, an hour of mixing and six hours of
settling prior to filtration. What you have to do depends on what you have to
deal with. And it's got to be evaluated case by case. But one thing you can
be sure of, if you have a sand filter and you don't add chemicals, you will
pass particles the size of bacteria, Giardia, and viruses.
Let me give you an example: Giardia bacteria are particles in the .3 to 4.0
micron size range. If you look at a rapid-sand filter, the smallest sand
gradation is going to have an effective size of maybe .25 but more likely .35
to .5 millimeters, or 350 to 500 microns. So you're talking about a field of
boulders from which you are trying to remove some pebbles. Obviously there's
a lot more to filtration than simple straining.
Where some ion exchange is taking place there is some increase of size and floe
formation and then removal. There's some absorption taking place. You can't
filter in the conventional public health sense unless you provide adequate pre-
treatment and you design that pre-treatment to deal with the problem at hand.
At Camas, they were adding about 10 to 12 parts per million of alum, whether
they needed it or not, 365 days a year. It was probably not doing a darn
thing, because they had all of about 10 minutes of detention time after an
addition of alum. Obviously, standby chlorination should have been provided.
If you're using alum, you could monitor for aluminum ion, and if you get a
significant passage you obviously are not forring the floe and removing it in
the filter.
(38
-------
WATER-SYSTEM EVALUATION AND CONTROL MEASURES
Operation and Maintenance Problems
Implicated in Giardiasis Outbreaks (Continued...)
The turbidity blip that comes througli a filter after backwash is something
we were concerned about. We installed a plant bypass to waste and found
a number of little cross-connections. (You'd think that no one should be more
sensitive to this than a water utility.) It goes back to the period of
design: turbidity was not considered a health-related concern. The plan
was to remove the big chunks, and if it had a few little cross-connections, no
one worried.
The Leavenworth watershed is in the Alpine Lakes Wilderness Area, one of the
most beautiful pieces of terrain on earth, and also one of the heaviest-
used areas by backpackers. The water is taken from Icicle Creek. The
parking lot to get people up into this wilderness area is adjacent to the water
treatment plant. They maintained a chlorine residual of sorts at Leavenworth:
.3 to .4 parts per million. Detention time was fairly short: 10 or 15 minutes.
Certainly not adequate by what we consider the situation to be now. Their
filter plant was a gravity filter plant, improperly operated. They had
chemical feeders, the ability to feed two primary coagulants, were set up for
alkilinity addition, plus alum, plus filter aid. The tanks had never been used.
They were bone dry, sitting down in the basement. Fortunately, the feed
equipment was there: all we had to do was fire it up. Their raw water turbidity
was about 1.2 and their treated water turbidity about .9, with no pre-treatment.
What that means is that they removed about 25% of the material coming in. After
not being able to bring that turbidity down despite a lot of work with pre-
treatment, we got down into the filters and started scratching around. This
is where we discovered that the majority of the media had left. . It was
replaced by some silt and organic material that made the level in the filter
beds look reasonable, but it was just muddy. (You could take a sample up to
the lab, put it in a jar, add some water, shake it up and it would look
like coffee.) In this case, they were inadequately cleaning the filter media
by inadequate backwashing.
At Camas we had a failure in disinfection , and a failure in pre-treatment.
The question was asked about the support media in the pressure filters:
the media down to the fine garnet was level and undisturbed. There was some
mounding in the coarse garnet beneath the fine garnet but it should not
have led to a problem. In theory, if you're intact through your fine-garnet
media, you should have had a layer there that could have done the job, given
adequate pre-treatment.
At Leavenworth, there were pi"oblems with disinfection, pre-treatment and
backwashing. It's possible, by failure to operate properly, to even wipe out
multiple barriers.
Camas is about 6,000 peonle, which is still a small utility. Leavenworth is
about 2,000-3,000. Camas actually had a fairly good staff that we were later
able to give some instruction and feel reasonably confident that they'd be
able to operate the filter plant properly and do a good job of it. At
Leavenworth, I don't think we ever felt comfortable that they were going to do
a good job with the operation and maintenance of that system. You're not going
to find utilities of that size that can put a man in the plant for the full
time of operation. That's a key, because the raw water is not going to stay
the same. This means the requirements for pre-treatment will vary.
-------
WATER-SYSTEM EVALUATION AND CONTROL MEASURES
Operation and Maintenance Problems
Implicated in Giardiasis Outbreaks (Continued...)
I'd like to suggest a couple of ways to help, if not make the system right, at
least to improve your odds. I mentioned the problem of pre-treatment with alum.
It's a careful balance of alum, alkilinity, temperature, and pll, and the odds
of staying in balance during a rainstorm in a small watershed are practically
nil. I'd like to suggest that you avoid alum as the primary coagulant on these
small utilities. Take a look at the possibility of using a polyelectrolyte
as the primary coagulant and back that up with a filter aid. The polyelectro-
lyte primary coagulant seem to be less sensitive to changes in water quality
than alum. rfhey are more expensive, but a lot less expensive to a water
utility than a waterborne disease outbreak. They require less operator skill.
Another thing I think needs more emphasis is the use of disinfection in the
control of these outbreaks. I noticed yesterday when somebody brought up the
question of disinfection to control Giardia, people on both sides of me said
you can't do it. And yet we're hearing that disinfection levels in the 1.0 to
2.0 mg per liter free residual at proper pH's, at proper temperatures, at
proper detention times, can provide a fairly good level of protection. Let me
throw out another possibility: if a utility doesn't have proper detention
time to allow a 1 mg per liter - 2 mg per liter dose, give some thought to
chlorinating at a higher dose, and then de-chlorinating.
The question of the effect of turbidity on disinfection was brought up. I
think the EPA has done some very good research on turbidity effects, which
is why we have a turbidity limit as a health-related parameter. Turbidity in
some forms exerts a strong chlorine demand, provides shelter for bacteria and
provides precursors for triahlomethane formation. In some of the utilities
we looked at, though, particularly when you're looking at a mountainous
region, you may have inorganic turbidity that doesn't cause problems. You may
be able to chlorinate at substantial levels without encountering some of the
problems normally associated with turbidity.
Reliability: make the thing reliable. Bob Willis from Portland made the
comment about the difficulty of getting the residual analyzed or getting a
loop system that worked properly. You're not going to be able to sell a
small utility on using that stuff anyway, even if it did work properly. But
what you can sell them on at a reasonable price is at least the use of an
automatic changeover yoke on a couple of cylinders, that'When the guy doesn't
^o up and check the cylinders except for a couple of. times a week, at least
there will be some chlorine running into the system, or a good chance of
chlorine running into the system.
I think there's enough information from Dr. Meyer's work and from work at EPA
for you to get a pretty good idea of doses of chlorine that would be required
under different conditions to provide some protection in areas where you
don't have filtration.
(40
-------
WATER-SYSTEM EVALUATION AND CONTROL MEASURES
Colorado Case Study [Rick Karlin, P.L.
Colorado Department of Health
Denver, Colorado)
Background
During the mid-1970*s the Colorado Department of Health became
increasingly alarmed about the occurrence of Giardiasis among residents
and visitors to the State. Although most of the infections were (and
still are) associated with day care centers and consumption of untreated
water by bikers, skiers and the like, concern over the vulnerability of
consumers of public water supplies began to mount.
Data available at that time indicated that extreme time-concentration
factors were necessary for the deactivation of Giardia lamblia cysts.
This coupled with the strong association between surface water and
Giardiasis led to the conclusion that filtration of all surface water is
necessary to adequately protect the public from Giardiasis.
Regulatory History
With the advent of the Federal Safe Drinking Water Act in 1974, and
subsequent EPA regulations, Colorado was required to significantly alter
their drinking water regulations. (Regulations went from a 2 sided
single page to 88 pages in length). New "Colorado Primary Drinking Water
Regulations" adopted in 1977 changed the pre-existing disinfection
requirement (imposed on all public water supplies) to include the
statement "Surface waters shall be disinfected by both chemical and
physical treatment, including filtration." This statement was added
principally to assure the removal of Giardia cysts and other particulates
capable of causing disease or of masking pathogens from chlorination.
To assure that the "filtration" message was not lost, "Disinfection"
was defined as "the effective killing or removal of pathogenic organisms
from public water systems by means or methods utilizing chemical and
physical treatment, including filtration and related processes such as
coagulation and sedimentation."
41)
-------
WATER-SYSTEM EVALUATION AND CONTROL MEASURES
Colorado Case Study (Continued...)
The "Disinfection" definition was added in a last minute effort to
assure filtration was properly "defined" and required. As with most last
minute crunch efforts, some Important details were overlooked.
Principally, the definition of disinfection, if literally interpreted,
required filtration of all water (including ground water). Secondarily
it described filtration and "related processes such as ..."without
directly requiring chemical pretreatment and sedimentation. Research and
plant data have long indicated that particulate removal is quite poor in
granular filters in the absence of chemical pretreatment. Therefore, the
1977 regulations, while attempting to require the proper filtration of
all surface waters had somewhat missed the mark.
The 1981 revision of the Colorado Primary Drinking Water Regulations
(brought about by the EPA regulation of trihalomethanes, sodium, etc.)
attempted to address the shortcomings of the "first generation"
filtration requirement.
All systems were required to disinfect and surface water suppliers to
filter as before. However, the definition of "Disinfection" was changed
to "the removal of pathogenic organisms from public water supplies by
chemical and physical treatment, including, for surface waters,
filtration and related processes such as coagulation and sedimentation."
To assure that a proper understanding of what is involved in the
filtration process if maintained in the regulation "filtration" is
specifically defined to mean "the physical and chemical process for
separating suspended and colloidal impurities from water by addition
of chemicals, sedimentation, and passage through a porous medium." An
excellent definition of conventional high-rate filtration process (if
I do say so myself). As indicated earlier, "filtration" without
adequate pretreatment is inadequate to assure the removal of Glardia
cyst size particles.
It appeared that all loopholes had been closed and flaws
corrected. All public supplies were required to disinfect and all
surface supplies to filter. However — in our zeal to properly define
"filtration" we had technically eliminated alternative filtration
techniques. Specifically neither diatomaceous earth (D.E.) nor slow
sand filtration generally lend themselves to chemical pretreatment.
(Coagulation gums up the works for both of these processes). Direct
filtration does not include a sedimentation step.
(42
-------
WATER-SYSTEM EVALUATION AND CONTROL MEASURES
Colorado Case Study (Continued...)
In practice, we have approved what we feel are properly applied
"non-conventional" filtration techniques. (D.E., slow sand and direct
filtration). We anticipate a third generation regulation more clearly
defining what pretreatment/filtration techniques will be acceptable.
Confirming Data
The appropriateness of the filtration requirement has been
confirmed by waterborne Giardiasis data collected over the last 18
years. Interestingly most of the data has been collected since the
institution of the filtration requirement.
In Colorado we have had 15 confirmed waterborne giardiasis
outbreaks associated with public water supplies. The time
distribution of these outbreaks is worthy of discussion specifically:
1965-1979 four outbreaks, 1980-1982 six outbreaks, 1982-present five
outbreaks. The most notable feature of this data is the large
increase in documented outbreaks beginning in 1980 (from 0.28 per year
from 1965-1980 to 3 per year from 1981 to 1982). We feel that this
apparent increase in outbreaks is in fact due to an improvement in our
investigation and reporting procedures.
Specifically, during this period (1980-1982) we were conducting
intensive waterborne disease surveillance under a special grant from
the USEPA and Center for Disease Control. The grant was given to
several states to determine whether more intense surveillance results
in a higher rate of documented disease and what surveillance methods
appear to be most effective. The specific results of this study are
available as a separate report, however, a few highlights are
appropriate for mention here.
During the study period a full time waterborne disease
"investigator" was added to the Department staff with the full time
assignment of follow-up of waterborne disease reports. Initially,
telephone surveys were conducted whenever an unsafe bacteriological
sample (exceeding coliform maximum contaminant level) was received.
No outbreaks (due to Giardla or other agent) were detected in this
manner.
43)
-------
WATER-SYSTEM EVALUATION AND CONTROL MEASURES
Colorado Case Study (Continued...)
Lack of "success" via this approach led to utilization of a
different technique, namely the follow-up upon reported potential
waterborne disease. Disease reports from citizens, local health
authorities, medical communities were investigated via phone surveys,
where appropriate, to determine the nature, extent and apparent cause
of enteric disease within a community. Whenever public water supplies
were implicated in outbreaks, engineering investigation as to
treatment deficiencies or breakdowns which may have led to the
apparent outbreaks were performed. Where appropriate, enforcement
actions were taken to assure correction of deficiencies and prevent
recurrence of outbreaks.
At the close of the study period, we decided to maintain the
surveillance program, and it is in place currently. Although the
program has apparently "increased" waterborne disease occurrence in
Colorado, it has also enabled us to identify and correct a number of
deficient water systems.
Review of the engineering aspects of all fifteen giardiasis
outbreaks revealed the following common features:
(1) Fourteen of the fifteen outbreaks were associated with
surface water supplies.
(2) None of the outbreaks occurred on a system equipped with full
treatment. Full treatment includes coagulaton/flocculation,
sedimentation, filtration and disinfection.
(3) None of the outbreaks was associated with violation of the
Colorado Primary Drinking Water Regulations/USEPA turbidity
standard (1.0 NTU).
(4) None of the outbreaks was associated with a violation of the
Colorado Primary Drinking Water Regulations/USEPA
bacteriological standard.
From these facts it can reasonably be concluded that meeting the
drinking water standards alone will not assure prevention of
Giardiasis, and in fact that only proper installation and operation of
full treatment on all surface water supplies can reasonably be
expected to prevent waterborne giardiasis outbreaks.
(44
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WATER-SYSTEM EVALUATION AND CONTROL MEASURES
Colorado Case Study (Continued...)
Enforcement Results
Inventory records in 1981 showed 25 surface water systems in
Colorado which lacked complete treatment, inspections in the meantime
have revealed five more, for a total of 30 systems failing to meet the
filtration requirement. Of these, 21 have plants under construction
as a result of either persuasion or coercion. "Coercion" in this case
means issuance of a legal Notice and Order to construct facilities.
All systems serving 500 or more consumers are now treating or
constructing treatment facilities.
There has been little "resistance" from the engineering community
or from the regulated community, in general, to the filtratin
requirement of the Colorado Primary Drinking Water Regulations.
A large portion of surface supplies are associated with the
tourist industry. The resort and other suppliers recognize the
potential damage which they may incur should they fail to provide a
safe water supply to the public. This coupled with a fairly
widespread educational effort has resulted in a high level of
cooperation from water purveyors.
In summary, we feel that the Colorado filtration requirement is
technically sound and public health effective. Its implementation has
been successful and its long-range effect should be the reduction of
waterborne disease.
45)
-------
WATER-SYSTEM EVALUATION AND CONTROL MEASURES
Water-System Evaluation/Risk Evaluation: Report of Workgroup 5
The EPA gave DJoA.lzgA.oup 5 the following AuggeAted diAcuAAion question*,:
- How do you detenmine the AiAk aAAociated with a wateA AyAtem?
What phyAical and chemical. chaAacteAiAticA oft a wato.fi Aupply
create a AiAk oft giaAdioAiA?
- Can we AeaLtAtically decide what hjj>k iA aAAociated with finding,
ftoA example, one GiaAdia cyAt in a chinking-water supply?
- ShouZd viability oft cyAtA be conAideAed in determining AiAk?
- How can wateA-AyAtem opeAatoAA be inftoAmed about AiAk evaluation
and control meatuAeA?
The EPA olLao AuggeAted the following poAAible ftinal product: Criteria ftor
determining when a wateA AyAtem iA at AiAk ftrom GiaAdia. RecommendationA
about how to inftorm oa educate water-AyAtemA operatorA about aAAeAAing
theiA water AyAtemA ftor potentLaZ GiaAdia AiAk, and about appropriate
control meaAuAeA ftor GiaAdia.
Summary:
The group looked primarily at two questions:
1. How do you determine risk associated with a water system?
2. Specifically, what physical and chemical characteristics of
a water supply create risk of giardiasis?
To simplify the issues involved, the group listed the following arbitrary
assumptions.
• Giardia is ubiquitous.
• Waterborne Giardia is a public-health problem.
• Viable organisms exist in surface waters (two-month survival.)
• Cysts found in water can be infectious to humans.
' Our focus is on Oregon water systems and Oregon priorities.
The group then came out with specific criteria for determining when a
water system is at risk for Giardia. Everyone agreed that even with a
(46
-------
WATER-SYSTEM EVALUATION AMD CONTROL MEASURES
Water-System Evaluation/Risk Evaluation; Report of Workgroup 5 (Continued...)
priority list established, the final determination of which system(s)
were at highest risk would rest with the professional judgement of
the investigator.
Determining the general risk associated with a water system:
1. What is the water source?
If surface:
- Is there human habitation upstream?
- Is there animal habitation upstream? In what proximity to
the water? What animal(s)?
- Do humans use the upstream area for recreation?
- Is there logging upstream?
- Is the watershed protected?
2. Water quality: what are the physical, chemical and microbiological
characteristics of the water?
3. What treatment does the system use? Is it reliable? Is it maintained?
4. What population is at risk?
5. Is there historical (epidemiologic) evidence of disease?
6. What is the finished water-quality record?
- Has treatment been consistently effective? (As determined by
such water-quality parameters as total coliform and turbidity
testing, biomass removal, fecal coliform, SPC, or Giardia tests.)
- Has the water had sufficient chlorine residuals on a consistent basis?
- Are the system's records adequate to determine the effectiveness of
the treatment?
7. What is the season?
- Winter: lower probability
- Spring, summer, autumn: higher probability
8. Operation and maintenance of the treatment facility:
- How is the plant maintained?
Is the operator skilled? Certified?
- What training is given the operator?
- How well does the operator understand what he or she is trying to
accomplish?
- How fast does the facility's staff turn over?
- How does the facility test its own quality? Does it have a lab?
1Equipment? Access to either?
-------
WATER-SYSTEM EVALUATION AND CONTROL MEASURES
Water-System Evaluation/Risk Evaluation: Report of Workgroup 5 (Continued...)
Determining what physical and chemical characteristics of a water supply
create risk of giardiasis:
Looking at the importance of the above items (#1 through #8), the group
determined priorities for them with respect to giardiasis risk.
Priority: Risk Factor:
1 Systems that use surface water, or
surface-influenced water
(Animal and human contamination that
can be seen, found or proved makes this
priority more obvious, but the risk exists
for all surface-related systems.)
Systems with no disinfection,
or systems with inadequate disinfection
(i.e., is the concentration and/or contact
time adequate?)
Systems with treatment not as efficient
or effective as other possible treatments
Systems with an epidemiological history of
disease
Systems with improper or inadequate
operations and/or maintenance
History of poor water quality
(48
-------
WATER-SYSTEM EVALUATION AND CONTROL MEASURES
Control Measures for Giardia in Water Systems
WohkgAoupA 6 and 7 weAe aAAigned the tame, topic and the following dUcuAAion
queAtionA:
11 a watch AyAtcm haA a heal oa potential Giahdia pAoblem,
what emergency mzaAuACA should be advised? What long-tehm
meaAuheA? (ilhat the ha.tion.ala bo.hA.nd each meaAuAe?
The. EPA AtiggeAted the. fiollouiing fctnal ph.odu.cti>: Recommended Ahoht- and long-tehm
meaAuAeA fioh. wateh. AyAtemt> with cuhAent oh potential GiaAdia phoblemA. Mcoauaca
&oh. Ay-item with no treatment, thoAC with dcA in faction only, and thoAC with
^utt treatment.
Ulohking Aepahately, the ghoupA came up with AimilaA AecommendationA. TheJji
Aepoh.tA ahst pAeAented a epaAately below.
Control Measures for Giardia in Water Systems: Report of Workgroup 6
The group began with some general discussion, and the setting of two arbitrary
assumptions (in order to simplify the issue.j Tne assumptions
the group set are:
' There is a thorough knowledge of the system, and
a risk-assessment has been made.
• By definition, the duration of the emergency is limited to 72 hours.
The discussion included such ideas as freezing, using the hot-water faucet,
and other possible emergency measures, but everyone agreed that these
were "special-case" measures, not to be bandied about generally for fear
of confusing the issue.
The group then divided the treatment measures into the EPA's suggested three
categories: "no treatment," "disinfection only," and "full treatment." The
measures the group determined for each situation follow.
49)
-------
EMERGENCY AND LONG-TERM TREATMENT FOR WATER SYSTEMS WHERE GIARDIA IS A POTENTIAL OR REAL PROBLEM
Emergency Measures
Interim Measures
Long-term Measures
System
with
No
Treatment
j. Put ou+ M-waterw/ater
notice. Ntfice should be 'm forcE
¦for three, da.ys.
Z. Cvmmuriic&te +& Public, what-
"ts be'wg done- provide.
OMVtnU0US notice-
3. implement emergencyAc-Hen
plan • Notify appropriate
agencies-
I- £*picr-e U HtaHpn " tA
-for-fabte reserveif5 "f^tfrv'onr
3, rvf-'i»itfe pufcCtc &Luuxfior\ ^ irtfrtV^Tcn.
/ -ity- ZcUYce cf £OKtfam"ma+TorA
develop a- flan h> deai iVi-Hi 'it, [fjiaiwfe-
a* "*cuVces" cp^ratfflri/.*^ finance prcWKi;
er e- tperttritig c^'&r cnpac.VJy->
&, trtteriM CcvrfTc\ rM. S«t" water-ttf««rwt+Tcn i*npi^»n6irk
/. Imftevn.ert' [oi^-term piwA Alterwai^ 5ou*re
-Xn5+all .
c«mta t+ +i me/ s¥eraae.(
v«/«+erfhed tyianfl^rwen+V
cperaWon^ controls
- foo -fc> ^ul|
2. ConfiKiue public 'irtfoona.+ion
2,. Tra\n; ec*Uca.-hf
c6rfif-y (ppetztfenrs.
System
with
Disinfectior
Only
1. Pvtf ouf- boil- vufcr/botf-\€£• s'jfe-
iA/0'"ter- ^ual'ify
7. Se-f- w«-+€V' conservation
*«€Asur Ai\f. fvJr Into
j. Iwiptement Jong--teriYV
pl-Fi^ al+«riiafe
-Gro -to-full +r€^.im€nh
z. upiraie 'improve
Ms\fifec*\CY\ .
3 . y?uJ?/i'c mftTfMaViPn-
Trtfirt, eJuca-fe
ce<-Kfy epewttors.
System
with
Full
Treatment
I- H above •
5". Rev'^W op&coMm
-to impxove, e^fu-fnt
qualify, awA 'iwpl£rfl£rtr
revised - CGo^-l•'
0/% Nrru)
j-t| above-
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-------
WATER-SYSTEM EVALUATION AND CONTROL MEASURES
Control Measures for Giardia in Water Systems: Report of Workgroup 7
Workgroup 7 approached the same topic as Workgroup 6, but from a
slightly different outlook. Instead of dividing the treatment choices into
"emergency, interim and long term," the group used "short-term" and "long-term."
In developing the chart on the following page, the group considered
efficiency and efficacy, what really works, relative cost, funding mechanisms,
simplicity and whether the suggested solution suits the system,
availability, owner motivation, and urgency.
After finishing the chart, the group came up with a slogan to keep in
mind when dealing with a problem that has caused an outbreak:
"Find It, Fix It, and Don't Forget It."
51)
-------
Systems with
No Treatment
Short-term Solutions
1. Issue "boil water" notice and maintain input
to media.
2. Establish the source of infection.
3. Establish disinfection appropriate to the
system.
4. Flush until effective chlorine residual level
is maintained within the system.
5. Continue monitoring and surveillance until
problem is controlled.
Systems with
Disinfection
Only
1. Issue "boil water" notice and maintain input
to media.
2. Establish source of infection.
3. Increase disinfection residual in mains.
4. Review disinfection system rapidly to see if
there are easily solved problems.
5. Continue monitoring and surveillance until the
problem is controlled.
Long-term Solutions
1. Perform an engineering evaluation.
2. Notify public health authorities.
3. Educate the community. upgrade
4. Select alternate source or/treatment.
5. Inform and educate legislators and
decision-makers.
1. Perform an engineering evaluation of the
water system.
2. Consider alternate sources or additional
treatment.
3. Get consultation, information and/or
technical assistance as needed.
4. Seek State-mandated improvement.
Systems with
Full Treat-
ment
1. Issue "boil water" notice and maintain
input to media.
2. Make a quick engineering review to see if
there is an obvious problem.
3. Establish disinfection with an effective
residual.
4. Establish a system to handle the media, and
to keep the media from scaring the public.
1. Perform an engineering evaluation of the
system to determine the problem.
2. If cause is an operational one, educate
operators and/or change procedures to
reduce risk of it happening again.
3. If cause is "a catastrophe," prepare a
contingency plan to handle such an event
in future.
-------
THE FUTURE: REGUUTORY REQUIKEMl-NTS AND RESEARCH NT,HI IS
On the fiinal day ofi the ccm.fieAe.nce., the workgroup* conc.entA.ated on the fiuXvAe.
Two looked a.t lA&ue* surrounding betting regulatory AeqLuAe.me.nt6, and
two looked at what fiuture research wa,6 needed. TheAe reporti fiollow.
Future Regulatory Requirements
Workgroups 9 and 10 handled the "Future Regulatory Requirement*" topic.
The EPA -suggested the following diicuAAlon que*ti.onb:
- Should GiaAdia be a regulated cLrinking-ivater contaminant?
- lb It pla.uAi.ble at this time to consider a maximum contaminant
level or a treatment standard?
Future Regulatory Requirements: Report of Workgroup 9
Current State and EPA Status:
The State has just adopted a rule that:
- requires "no pathogens" in finished
- defines pathogens,
- doesn't require testing, and
- could mean that finding any Giardia
the "no pathogen" rule.
The EPA's status:
The Safe Drinking Water Act requires regulation of substances that
pose a hazard to health. Giardia meets that test. Therefore, the
EPA has two choices:
1) Set a maximum contaminant level (MCL) for Giardia, and set testing
requirements for it, or
2) If good testing isn't available, set a treatment requirement.
In the current rulemaking, a treatment requirement may be the choice.
That requirement would probably be to filter surface water, with a
state regulatory agency to determine cases in which filtration isn't
necessary. (The requirement would probably take into account the
costs of "reasonably available technology" it would require.)
53)
drinking water,
cyst is a violation of
-------
THE FUTURE: REGUUTORY REQUIREMENTS AND RESEARCH NEEDS
Future Regulatory Requirements: Report of Workgroup 9 (Continued. ..)
Group Consensus:
The group believes that Giardia shouldn't be a regulated contaminant in
drinking water. It agrees with the EPA that devising an MCL isn't
feasible, so mandatory treatment of surface-water systems must be the option.
The group recommends such mandatory treatment take the following into
account:
- System size, source and vulnerability to Giardia, and
- Some decentralized decisionmaking process should be set up for
making decisions about specific water systems.
rlhe group determined the following considerations an agency which determines
adequate treatment should address:
1. The water source: Is there activity in the watershed? Is it animal?
Is it human?
2. What is the quality of the raw water?
What is the form of the turbidity? What are its levels, and what is
the variability? Is microbiological contamination present? At what level?
3. The availability or potential availability of operators with skill
enough to perform or operate the selected treatment system.
4. Whether or not the treatment is possible as recommended, given the
physical limits of the system:
Disinfection -- determine time available, pi I, temperature, type of disinfectant
- Filtration, with appropriate pre-treatment -- rapid sand, slow sand
Cost of facilities in relation to communities' ability to finance amortization
of capital and annual costs.
(54
-------
Tfff: FUTURE: REGULATORY REQUIRF.MFATS AND RESEARCH NEEDS
Future Regulatory Requirements: Report of Workgroup 10
Background:
The Safe Drinking Water Act requires regulations for any contaminant
that "adversely affects public health," as explained in Workgroup 9's
report. Since (despite the question of "how adversely?") Giardia
undoubtedly does affect public health, the EPA will probably regulate
Giardia levels within the next year. It has two choices of method:
1. To set a maximum contaminant level and sample water, or
2. To determine and recommend a treatment technique.
Although there may be monitoring flexibility in a regulation established
by the EPA, probably the requirements wouldn't vary nationwide.
In Oregon, the State Health Division requires "no pathogenic organisms"
present in finished water (as of 9/20/83). Routine pathogen sampling
isn't required, but the Health Division can require it when it wishes.
Discussion:
The group talked over the fact that Oregon's population will be increasing,
and as a population increases, it puts pressure on all finite resources.
In the case of water, the probable result will be a move to poorer-quality
sources. This makes adequate treatment all the more vital.
Some group members offered the opinion that since the rules are set for a
worst-case scenario, it seems that the regulated systems have to spend a
lot of money for little benefit.
The group agreed with the EPA's view that an MCL and sampling water were
not feasible. Reasons given included: we lack information on the infective
dose, sampling and analytical techniques can give a false sense that
everything is fine, and determining viability of cysts is costly in time
and money.
The real problem in setting and recommending a technique is the fact that
a test showing Giardia to be absent doesn't guarantee that it won't be
absent in the next day's test (i.e., the testing can give false negatives).
But even with that shortcoming the problems associated with the MCL approach
are so much greater that the group agrees with the EPA that the treatment
approach is preferable. Ideas include disinfection, filtration, multiple
barriers, et al (as presented in other workgroups), including watershed
control.
55)
-------
TME FUTURE: REGULATORY REQUIREMENTS AND RESEARCH NEEDS
Future Regulatory Requirements: Report of Workgroup 10 (Continued...)
Trends Future Regulations Should Address:
Given all it discussed, the group brainstormed three major trends it could
foresee in the next one to five years that future regulations must take
into account. Since "solving for Giardia also solves for other water
problems," these trends apply to drinking-water regulation in general,
as well as to Giardia issues in particular.
1. Increasing pressure on finite resources (in this case, water) will force
moves to sources of lower quality. This, in turn, will force more
treatment.
2. Additional efforts to increase tourism and attract new business to
the state will make the general public more aware of and supportive
of better water (or at least of maintaining acceptable levels). The
economics of good water versus the liabilities of bad water will be
increasingly important.
3. Continued research will identify new analytical methods and treatment
techniques, and/or improve old ones. Therefore, future regulations
should be worded in such a way as to allow improved methods to supersede
the methods they specify. (In one state, the law was so specific on
the method to use that it inadvertently prohibited use of a better
method that came along after it was set.) Since laws take time and
trouble to change, it's easier to add wording for flexibility when
they're being formed in the first place (along the lines of, "until
upgraded by new data" or "until made obsolete by a proven, newer
method.").
(56
-------
THE FUTURE: REGULATORY REQUIREMENTS AND RESEARCH NEEDS
WofikgAoupA 11 and 12 bnouinAtome-d tiAt6 o{) u)ka£ -ii, ntzdtd ion. ^txtuAZ
G-icoidia tiM&aAch. The EPA Augg
-------
THE FUTURE: iREGULATORY REQUIREMENTS AND RESEARCH NEEDS
Future Research Needs: Report of Workgroup 12
The group identified the following as useful directions for future research.
(See also Workgroup ll's report.)
1. More efficient, more sensitive and more economical methods of
detecting Giardia cysts in water.
2. From a biological standpoint:
Methods of differentiating Giardia strains
- Host-specificity studies: are specific hosts affected by specific
Giardia strains and no other?
What animals are reservoirs for Giardia cysts?
- What are alternative indicators of fecal contamination of water?
- Further encystation studies towards possible new ways to break the cycle
Less costly ways (in time and money) to determine viability of
cysts found in water
- Further research on methods for culturing Giardia,and their effectiveness
3. From an epidemiologic standpoint:
Host-specificity studies (learning characteristics of specificity to
allow pinpointing of risk groups)
- Transmission studies, including cross-species transmission
- What is the natural history of the disease?
- More on the immune response: why and how does it come about?
- More effective methods for diagnosing human infections
- Surveillance: how do we link cases to the source of infection?
- Human-treatment methods, chemotherapy
4. Control technology:
- Water-treatment methods: effective methods of inactivating
Giardia cysts
New methods
- Studies on treatment of water vs. treatment of people
- Definitive guidelines for disinfection (chlorine, halogens, ozone,
ultraviolet, etc.) and minimum treatment requirements.
- Less costly technologies of water treatment for small systems
- Techniques to simplify operation and maintenance of water-treatment systems
- Recommendations for evaluating efficiency of small-quantity water-
treatment systems at point of use.
5. Examination of the question: does the problem Giardia poses justify
spending more money on research? (It makes large numbers of people
sick. On the other hand, it doesn't kill anyone. How vital is more research?)
(58
-------
INFORMING PEOPLE ABOUT ("ITARDIA ISSUES
Workgroup 1's topic was "Public Information." The EPA suggested the
following discussion questions :
Vo we need to get , ok people on water systems known to
have potential Giardia problems? Jf so, what do we tell these people?
- Vo we need to get -information to physicians on GlaJidia problems
o side-effects of treatments? What Is the best way to get the
information out to the physicians and the public?
- Vo other groups need information on Giardia?
The EPA also suggested the following possible final products: A List of
segments of the public that need information on Giardia, including what
specific information each segment might need. A recommended method to get
the information out to these people.
Public Information: Report of Workgroup 1
The group agreed that giardiasis is a major health problem. Once that was
agreed, the group identified four basic public-information problems:
1. Identifying community groups to address about Giardia,
2. Deciding what to tell them,
3. Deciding how to tell them, and
4. Offering information about what they can do.
The group came up with the following suggestions and conclusions.
1. Identifying Community Groups to Address
The group identified two types of audience for information: "everyone," since
everyone is in at least one risk group; and special risk groups such as
backpackers, day-care centers, and pet owners.
2. Deciding What to Tell People
A general brochure should be available for the general public. In addition,
brochures with more specific information should be available for special risk
groups. The matrix on the following page addresses the question of what
information should go to what specific audience.
-------
INFORMING PEOPLE ABOUT GIARDIA ISSUES
3. How Do We Tell People?
It was the group's consensus that a general brochure, plus brochures
addressed to specific groups, are the best way to reach people. Also
discussed was the idea that a brochure written by a single agency would be
better for spreading the general information than having different agencies
write different ones. (Concern was voiced that otherwise agencies might
waste energy "re-inventing the wheel.") The suggestion arose that a central,
coordinating agency should develop the material. Then local, state, and
national groups could disseminate it.
4. Other Public-Information Routes or Approaches
The group also identified the following ways an agency could reach the
public with Giardia-related information:
- press releases,
- dissemination through special groups, such as the Boy
Scouts or Girl Scouts,
- a "Giardia Awareness Week,"
- having speakers available to present the topic to public
groups.
(See Appendix E for an example of an EPA handout about Giardia for
backpackers and campers.)
-------
INFORMING PEOPLE ABOUT GIARDIA ISSUES
Public Information: Report of Workgroup 1 (Continucd...]
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X
X
X
X
X
X
X
X
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What is giardiasis?
X
X
X
X
X
X
X
X
X
What causes giardiasis?
X
X
X
X
X
X
X
X
X
flow is giardiasis contracted?
X
X
X
X
X
X
• Fecal-Oral
X
X
X
X
X
- Pets
X
X
X
X
X
- Children
X
X
X
X
• Contaminated water supply
X
X
X
X
• Untreated water
X
X
X
X
X
X
X
X
What are the symptoms of giardiasi
X
X
X
X
X
X
X
How do I confirm I have giardiasis
(Get medical confirmationJ
*
*
Temporary first-aid treatment
X
Treatment and side-effects
X
X
X
X
X
Emergency disinfection
X
X
X
X
X
X
X
X
Prevention
X
X
X
0
X
X
• Proper environmental
sanitation
X
X
X
X
• Personal hygiene
X
X
X
X
X
X
Followup information
X
X
X
Exclusion
61)
* drink fluids to prevent dehydration
o these people may be carriers, so need to know how to prevent transmission
-------
INFORMING PEOPLE ABOUT GIARPTA ISSUES
Comniunieating about Giardia-related Issues among Concerned Parties
VuAing the couAse ofi vooAking on 1 SuAveillance ^o>i i/JateAboAne GlaAdiasis,'
ljJon.kgM.oap S came, up with a dififieAent topic that Aelated to GiaAdia:
that ofa communications between vcuiioas people and gAoups that aAe concerned
about Gi.aA.dia-delated pAoblemi, and how valuable, the people i.n the convenience
weAe finding the chance to talk and pnoblem-solve with each otheA. AfiteA
they liniAhed theiA suAveillance topic, they came up with the following
Ideas about communications.
Second Report of Workgroup 8
Problem Statement: General communications among and between all parties
affected by waterborne disease could be improved.
Groups and people meant by "all parties affected:"
water purveyors
association representatives
County Health people
the Environmental Protection Agency
laboratories
the Association of Oregon Counties
legislators
the State Health people
Water Resources
Inter-government Relations people
the League of Oregon Cities
Suggested Solution: A yearly forum of all parties.
Purpose: To identify each party's water program direction,
To share what has been done,
To develop consensus answers to the following:
- What are Oregon's main drinking-water problems?
- How can the group unite to get action on these?
To share resources on common problems.
Benefits:
1. Face-to-face contact with the people you're dealing with.
2. Solving water problems for Giardia also solves other water problems.
3. If diverse groups pooled resources, they could save money on programs
necessary to all.
When the workgroup presented this information to the entire conference,
the presentor challenged the conference to act on this idea by saying,
"The only thing better than a fantasy is a memory."
(62
-------
FINANCING FOR WATER-SYSTEM IMPROVEMENTS
Vave Phelps of the Oregon State. Health Division p-fiziQ.nto.ci current sources
of financing for iMt
-------
FINANCING FOR WATER-SYSTEM IMPROVEMENTS
Financing for Water-System Improvements: Report of Workgroup 4 (Continued...)
Problems surrounding the issue Strategies
Lack of clear understanding of
the Giardia/water/money relationship
Need a major public effort:
Research: on other diseases,
effective treatment, infection
levels, cost/effectiveness
studies, and the Giardia/
turbidity relationship.
. Statistical analysis of the
epidemiology of Giardia:
water/day care/other source
Lack of money for operations/maintenance
and training of operators
Set a mandatory certification
program for operators.
Obtain more training money from
state, federal, or local-rate-
structure sources.
State could require conpliance
with comprehensive planning rules,
Funding agencies could require
long-term fiscal planning.
Funding-agency process doesn't address
the needs of the water system very well.
Make funding priorities
consistent among agencies.
Establish a fund earmarked
for water.
(64
-------
GLOSSARY
Asymptomatic carrier Epidemiologically, an individual or member of an
animal population that has been infected by a disease causing organism and
harbors the orqanism in its body but does not exhibit symptoms of the
disease.
CI7 The chlorine molecule. In the gas state, chlorine normally occurs
as two chlorine atoms (chemical symbol: CI) bonded together, hence C12-
Contact time In water treatment, the amount of time that a chemical,
particularly a disinfectant such as chlorine, is allowed to remain in
contact with the water to be treated. The effectiveness of chlorine
disinfection is directly related to the chlorine contact time.
Control Measures In water treatment, steps taken by a water utility or
regulatory agency to prevent contamination of the water system or to prevent
transmitting pathogens through the water system. Increasing chlorine
contact time in the water system is an example of a control measure.
Cost effectiveness study The process by which the specific dollar costs of
taking some action are compared to the reasonable value of the result of the
action. For example, the cost of adding a new water reservoir for
increasing chlorine contact time could be weighed against the value of
better health protection for the water system's customers. (As in this
example, it is often difficult to assign a reasonable value to the effects
of the proposed action.)
Cross connection Links, usually plumbing links, through which it is
possible for contaminating materials to enter a potable water system.
Cyst In biology, a capsulelike, membrane covered body. Certain organisms,
such as Hiardia, form cysts in.the resting or dormant stage of their normal
1 ife cycles.
Disinfection The process by which pathogenic organisms are killed.
Usually, drinking water disinfection is accomplished by some physical means
such as boiling or irradiation with ultraviolet light, or by chemical
processes such as chlorination.
Encystation The process of forming cysts in the life cycle of certain
organisms.
Endemic Refers to something, such as a specific disease, which is
prevalent in or peculiar to a particular locality or group, (e.g.,
giardiasis appears to be endemic among beaver in Colorado.)
Epidemiology The study of rapidly spreading contagious diseases.
Excystation The process of emerging from or passing out of the cyst stage
in the life cycle of certain organisms.
False negative In water testing, the occurrence of a negative test result
when the material tested for was actually present in the sample. In Giardia
-------
GLOSSARY (Continued. ..)
testing in drinking water, for example, it is not uncommon for the test
results to show that no Gi ardia organisms were found when, in fact, Gi ardia
organisms may have been present in the sample.
Fi nished water In a water system, this refers to water that has been
treated and is ready for drinking. (See also raw water.)
Gi ardia Short for Giardia lamhlia, a flagellated protozoan parasite which
inhabits the small intestine of amphibians, birds, and mammals. In recent
years, Gi ardia has become one of the most commonly identified human
intestinal parasites.
Gi ardias is The gastro-intestinal disease caused by Gi ard ia infection.
Symptons include nausea, explosive diarrhea, gas, bloating, cramps, loss of
appetite, and if untreated, loss of weight.
Immune component A molecule or particle, such as an antibody, which
imparts immunity or partial immunity.
MCL Maximum contaminant level, the maximum permissible level of any
contaminant in drinking water. MCLs are set by state and federal
regulations for a number of contaminants, such as arsenic, mercury, coliform
bacteria, and certain pesticides and herbicides.
Mo/1 fand mq/1 free residual) Milligrams per liter, a chemical unit
describing the concentration of a substance in one liter of a solvent
(usually water). "Mo/1 free residual" is the concentration of certain
chlorine compounds or molecules used as disinfectants in water.
Mutagen Any agent that causes a biological mutation, a heritable
alteration of the genes or chromosomes of an organism, (also mutagenic and
mutagenicity)
NTU Nephelometric turbidity units, a measure of the cloudiness of water.
(See also turbidity.)
Pathogen Any agent that causes disease, commonly a microorganism such as a
bacterium or, in this case, a protozoan - Giardia. (also pathogenic and
pathogenicity)
Protected watershed A watershed which is fenced, patrolled, or otherwise
regulated to prevent the introduction of contaminants.
PVA Polyvinyl alcohol, a laboratory preservative used in Gi ardia analysis
that does not destroy the Giardi a trophozoite.
Rapid sand filter A water treatment unit consisting of a tank; several
layers of filter material (media) such as gravel, anthracite coal, and sand;
and a system of pipes to deliver water to the filter; remove water that has
passed through the filter; and wash the filter. A typical operating rate
a rapid sand filter is 2 gallons per minute per squate foot of filter
surface. (See also slow sand filter.) (66
-------
GLOSSARY (Continued...)
Raw water In a water system, this refers to water from the water source
that has not been treated and is not ready for drinking. (See also finished
water.)
Regulated contaminant A drinking water contaminant, such as coliform
bacteria, for which state or federal limits or treatment requirements have
been established.
Reservoirs Epidemiologically, a group of animals or individuals that carry
a pathogen and are capable of transmitting the pathogen to the environment
or to other individuals.
SOWA The Safe Drinking Water Act (P.L. 93-523) signed into law by
Richard Nixon on December 16, 1974.
Shedding (and intermittent shedding) The process of releasing pathogenic
organisms, either continuously or intermittently, to the
environment. Tyoically, refers to beavers or other animals shedding Giardia
cysts in their feces.
Sixty-minute retention (See contact time.) This refers to a contact time
of 60 minutes.
Slow sand filter A water treatment unit consisting of a large shallow
tank, a layer of sand usually ? to 3 feet thick, and a system of pipes to
supply water to the filter and to remove the filtered water from the bottom
of the unit. A typical operating rate for a slow sand fiIter is 0.03 to
0.05 qallons per minute per square foot of fiIter surface. (See also rapid
sand fiIter.)
Survivabi1ity Epidemiologically, the ability of a pathogenic organism,
such as a Giardia cyst, to survive in a certain environment. (See viability.)
Teratogen Any agent that causes a malformation during the embryological or
prenatal development of an organism. In other words, an agent that causes
birth defects, (also teratogenic and teratogenicity)
Testing (for coliform, turbidity, standard plate count, biomass, etc.) In
the context of this document, the process of collecting samples of water and
analyzing the samples for some specific substance.
Trophozoite A stage in the life cycle of Gi ardia organism. The Gi ardia
trophozoite stage normally occurs in the intestine of the host.
Turbidity Commonly refers to the cloudiness of water. Technically,
however, turbidity is a measurement of the light-scattering characteristics
of the water.
Viabi1ity The ability of an organism to survive in a given environment.
(See also survivability.)
67)
-------
APPENDIX A:
LIST OF CONFERENCE ATTENDEES
-------
APPENDIX A: LIST OF CONFERENCE ATTENDEES
Jeannette Bobst
Lane County Health Department
1.35 Sixth Avenue
Eugene, Oregon 97401
Paula Stonier
Oregon Public Health Lab
Oregon State Health Division
State Office Building, Rin 711
"1400 S.1V. 5th
Portland, Oregon 97201
Jim Boy ds ton
Oregon State Health Division
Sue Cameron
Tillamook County Health Dept.
Courthouse
Tillamook, Oregon 97141
Larry Eisele, U.S.
Washington County Health Dept.
150 N. Pirst Avenue
Hi llsboro, OR 97123
Eugene Water Electric Board
PO Box 10148
Eugene, Oregon 97440
Jeff Fontaine
Drinking Water Supply
U.S. EPA
^.15 Fremont Street
San Francisco, CA 94105
Dr. Laurence Foster, MD
Deputy Epidemiologist
Oiegon State Health Div.
Smith Tower Building
Seattle, WA 98104
Mike Cearheard
EPA, Oregon Operations Office
522 S.W. Fifth
Portland, Oregon 97204
Jean Knight
EPA, Oregon Operations Office
John Graham R.S., Supervisor
Douglas County Health Department
621 Madrone
Roseburg, Oregon 97470
Dr. Charles P. Hi.blcr, PVM, Ph.D.
Director, Wild Animal Disease Ctr.
College of Veterinary Medicine
Colorado State University
Fort Collins, Colorado 80523
Maryanne Hill, President
Oregon Association of Water
Utilities
PO Box 27
Government Camp, Oregon 97028
John Huffman
Oregon State Health Division
Roy Jones
EPA, Region 10
1200 Sixth Avenue
Seattle, WA 98101
Dennis Juranek, D.V.M., M.Sc.
Assistant Chief, Protozoal
Diseases Branch
Center for Disease Control
Building 8, Rm. 103 - Chamblee
Atlanta, Georgia 30333
Rick Karlin, P.E.
Colorado Dept. of Health
4210 E. 11th Avenue
Denver, Colorado 80220
William R. Keyser, Director
Dept. of Water Supply § Treatment
City of The Dalles
6780 Reservoir Road
The Dalles, Oregon 97058
John Kirner
Water Division
City of Tacoma
PO Box 11007
Tacoma, WA 98411
(A1
-------
APPENDIX A: LIST OF CONFERENCE ATTENDEES
Mark Knudson, P.I:.
Bureau of Water Works
City of Portland
1120 S.W. 5 th Avenue
Portland, Oregon 97204
Edwin C. Lippy, P.E., Chief
M/S 314, U.S. EPA
Health Effects Research Laboratory
26 West St. Clair
Cincinnati, Ohio 45268
Robert Mc Alister
University of Oregon
Health Sciences Center
3181 S.W. Sara Jackson Park Road
Portland, Oregon 97201
Nancy Mc Tigue, Environmental Engineer
Drinking Water Branch
U.S. EPA
1860 Lincoln Street
Denver, Colorado 80295-0699
Dr. Ernest A. Meyer
Professor of Microbiology
University of Oregon
Health Sciences Center
3181 S.W. Sam Jackson Park Road
Portland, Oregon 97201
Bill Mullen
EPA, Region 10
1200 Sixth Avenue
Seattle, WA 98101
Larry Payette
EPA, Oregon Operations Office
Dave Phelps
Oregon State Health Division
Don Pickens
Wolf Creek Highway Water District
1850 S.W. 170th Avenue
Beaverton, Oregon 97005
A2)
Gary Pippin
Wolf Creek Highway Water District
1850 S.W. 170th Avenue
Beaverton, Oregon 97005
Byron R. Plan, Regional Sanitarian
M/S LD-11
Water Supply and Waste Section
Department of Social and Health
Services
Olympia, WA 98504
Elizabeth Sazie, Health Officer
Benton County Health Dept.
530 N.W. 27th Street
Corvallis, Oregon 97330
Charles Schade, M.D.
Multnomah County Division of Health
426 S.W. Stark Street,.9th floor
Portland, Oregon 97204
Lois Arm Shearer, Epidemiologist
California Dept. of Health
4326 Nelson Drive
Richmond, CA 94803
Steve Sorenson
US Geological Survey
2800 Cottage Way, Rm W2235
Sacramento, CA 95825
Gary Stevens, R.S.
Jackson County Public Health Center
1313 Maple Grove Drive
Medford, Oregon 97501
John Stoner, R.S.
Oregon Water Treatment Certification
Program
1065 High Street, Suite 4
Eugene , Oregon 97401
Gene Thomas, P.E.
U.S. Forest Service
Department of Engineering
PO Box 3623
Portland, Oregon 97208
-------
APPENDIX A: LIST OF CONFERENCE ATTENDEES
Jay Vasconcelos, Microbiologist
M/S 337
U.S. EPA
1200 Sixth Avenue
Seattle, WA 98101
Nancy Wentworth
Drinking Water Branch - W1I 550
U.S. EPA
401 M Street SW
Washington, D.C. 20460
Bob Willis, P.E.
Bureau of Water Works
City of Portland
1120 S.W. 5th Avenue
Portland, Oregon 97204
Harry Youngquist, P.E.
Lane County Land Management Division
Department of Public Works
Public Service Building Concourse
125 E. 8th Avenue
Eugene, Oregon 97401
Ron Hall
State Health Division
Floyd Frost, Epidemiologist
M/S B17-9
Office of Public Health Laboratories § Epidemiology
Smith Tower Building
Seattle, WA 98104
(A3
-------
APPENDIX B:
GIARDIASIS, TIE ILLNESS
The {o-LZouxing chaAtb AuppoAt Lajviy FoAteA.'* talk, "GiaAdLcu>-iA,
the IZlneAA," ivkich
-------
APPENDIX B: GIARDIASIS, TOR ILLNESS
Table 1: Treatment
Drug
Adult Dose
Pediatric Dose
Drug of choice:
Quinacine HCL
(Atabrine)
Alternatives:
Metronidazole
(Flagyl)
Furazolidone
(Furoxone)
100 mg 3x daily
for 5 days
250 mg 3x daily
for 5 days
100 mg 4x daily
for 7 days
2 mg/kg 3x daily
for 5 days
(Max. 300 mg/d)
5 mg/kg 3x daily
for 5 days
1.25 mg/kg 4x daily
for 7 days
^From The. Medt&zZ Lt££&i on Vauqa and TheJiaputlcA,
January 22, 1982; 24(601):5-12
Table 2: Side Effects of Treatments
Drug Side Effects
Quinacrine Frequent: dizziness, headache, vomiting, diarrhea,
Occasional: toxic psychosis, insomnia, blood dyserasias,
nail pigmentation, rash
Rare: liver damage, seizures, severe dermatitis
Metronidazole* Frequent: nausea, headache, dry mouth, metallic taste
Occasional: vomiting, diarrhea, insomnia, weakness,
dizziness, paresthesias, rash
Rare: ataxia, encephalopathy, pseudomembranous colitis,
neutropenia
Furazolidone Frequent: nausea, vomiting
Occasional: allergic reactions, headache, orthostatic
hypotension, hypoglycemia, polyneuritis,
drug interactions
Rare: Hemolytic anemia in infants under age 1, and in
persons with G-6-PD deficiency
^Carcinogenic in mice and mutagenic in bacteria. Not FDA-approved for this use.
-------
APPENDIX C:
CONCENTRATING, PROCESSING, DETECTING AND IDENTIFYING
CTARDTA CYSTS IN WATER
The. fio-ttouiing pagzb con£cu.n background i.n&oAmation iuppoAting
Jay l/cu>conce.lo4' talk, "Me.thocU> oi Testing jot G-La/idLa in Water."
PlzaAe. t> talk (pp.14 through 16} £oh. ^u/ithei
information^and ion. an outline oft the modified EPA Con^enAuA
Method.
-------
APPENDIXC: CONCENTRATING, PROCESSING
DETECTING AMD IDENTIFYING GIAROIA CYSTS IN WATER
METHOD
INVESTIGATOR (S)
RESULTS
1. Membrane Filtration
CelUPosic
(47mm-0.4.Hum)
Polycarhi nate
(293mm-
Chang and Kabler
USPHS, 1956
Pyper, DuFrain and Henry Eng
198?, (unpublished)
Generally unsuccessful
Passing 1 gal/min at
10 PSI. 15-1800 gal
total
2. Particulate Filtration
(diatomaceous earth, sand,
etc.)
3. Algae (Foerst) Centrifuge
Shaw et al, 1977
Juranel<,~T979
Holman et al, 1983
DHHS, Washington
Generally good removal
but poor eluation
Good rapid recovery,
but limited in field
use
4. Anionic and Cationic
Exchange Resins
5. Epoxy-Fiherglass Balston
Tube Filters
(10"-8um)
6. MicroDorous Yarnwoven Depth.
Filters
(7 and 1um orlon and
polyprolvl ene)
7. Pellican Cassette System
8. Filterwashing Apparatus
Brewer, Wright State UN.
(unpublished)
Riggs, CDHS Lab, Berkley, CA
(unpublished)
Jakubowski, Erickson, 1979 and
1980, EPA-Cincinnati
Mi Hi pore Corp.
(unpubli shed)
DuWalle, U. of Wash., 1982
(unpubli shed)
Generally unsuccessful
Overall recovery 20-80
percent
Recovery 3-15 percent
Extraction ave. 58
percent
May be useful for
processing filter
washings
Claims 75 percent
recovery from orlon
filters
TABLE 1
(CI
-------
APPENDIX C: CONCENTRATING, PROCESSING,
DETECTING AND IDENTIFYING GIARDIA CYSTS IN WATER
PRIMARY CONCENTRATION AND PROCESSING METHODS
1. MEMBRANE FILTER (MF) METHODS
a. Celulosic (mixed esters of cellulose)
1. Chann and Kabler in 1956
First to use MF for cyst recovery. Recovered 20-42 percent at cyst
concentration of 3, 5, and 10 cyst/gal. - nn cyst found at
1 cyst/gal.
2. Method was used in 1965 Colorado outbreak (Moore, et al^, 1969) using
?. liter size water samples from 10 sites. No cysts~were detected.
Use cellulosic filters have generally not been successful in
demonstrating cysts in drinking water.
b. Polycarbonate (PC) Filters
1. Luchtel and Colleages in 1980 used 293 mm, 5.0 um pore size
nucleooore (PC) filters to concentrate formalin-fixed. G. lamblia
cysts from 20 L tap water samples. Recovery rates of approximately
75 percent were reported.
2. Pyper of DuFrain and Henry Engineers claim good recovery with same
nucleopore filter at a flow rate of 1 gal./min., not over 10 PSI,
passing 15-1800 gal. in just over 24 hours.
c. Even with those claims by Pyper and Luchtel, the MF Method has only once
(Aspen, 1965) been successful in demonstrating cysts in water--probably
because:
1. Inability to process a sufficient volume.
2. Inability to remove cysts from filter.
3. Cysts weren't present at time of sampling during or after outbreak.
2. PARTICULATE FILTRATION
a. SAND - CDC (Shaw, 1977) used high-vol filtration through swimming pool
sand filter (280,000 gal. total over 10 days) - was backflushed into 55
gal. drums and coagulated w/alum. Concentration fed to beagle puppies
and after treatment (cheesecloth to wire screening to 30 nm MF to
centrifuge) was examined microscopically. First time cysts observed in
water supply after concentration.
b. Diatomaceous earth (HE) - CDC (Juranek, 1979) used DE to remove cysts
from seeded water. Problem was that cysts couldn't be removed from DE
particles. Brewer (1983) claims 5.2-31.1 percent recovery from DE
backwash. Retention through 3 forms (celita 505, HyFlo-Supercel and
celite 560) at cyst concentration ranging from 6-16,000 cyst/L. Recovery
range between 66-100 percent.
-------
APPENDIX C: CONCENTRATING, PROCESSING,
DETECTING AND IDENTIFYING GIARDIA CYSTS IN WATER
3. ALGAE CENTRIFUGE
a. Was found to recover more cysts (IOX) than a series of MF-filters and
nylon screens: 5 vs. 1 day by MF.
b. May be impractical in field because of power requirement.
c. If used in lab, 1 large single sample collected in the field could miss
cyst.
d. May find application for concentration cysts from orlon filter washings.
4. ANIONIC AND CATIONIC EXCHANGE RESINS (Brewer - unpublished)
a. Based on hypothesis that cysts could be attracted to charged surfaces,
cysts have a charge of approximately 25mV at pH 5.5 which increases in
electro-negativity as the pH rises to 8.0.
b. Charge attraction techniques have been used for concentration of both
bacteria and viruses in water.
c. Five exchange resins were tested:
(1. 49 percent recovery from anionic Dowex 1-XY columns
(2. 38 percent recovery from cationic Dowex 50W-X8 columns
d. Compared to parallel tests w/diatomaceous earth, exchange resins less
efficient in retention.
5. BALSTON EPOXY-FIBERGLASS TUBE FILTERS
a. Riggs of CSHD, Viral and Rick. Lab., can filter 500 gallons drinking
water thru 10" - 8 pm Balston tube filter.
b. Backflushes w/1 L 3 percent beef extract or solution of 0.5 percent
potassium citrate.
c. Concentration is centrifuged w/40 percent potassium citrate and middle
layer filtered thru 5 n polycarbonate filters.
d. Uses direct immunofluorescence antibody technique for detection and
identification.
e. Claims 20-80 percent efficiency in collection, preprocessing and ID.
6. MICROPORQUS YARNWOVEN DEPTH FILTERS
a. In 1976 EPA develooed a concentration-extraction method involving large
volumes of water thru microporous yarnwoven orlon-fiber filters.
b. This method has been tenatively adopted as the "method of choice" for
concentrating cysts from water supplies.
(C3
-------
APPENDIX C: CONCENTRATING, PROCESSING,
DETECTING AND IDENTIFYING GIARQIA CYSTS IN WATER
c. Since Initial studies which showed only 3-15 percent recovery with a mean
of 6.3 percent and a 58 percent extraction rate, several changes have been
made which may have increased the retention rate to >20 percent.
d. It was the first method successfully used to detect cysts in the
distribution system of a community water supply.
e. Is the recommended filter to be used by the EPA consensus method.
7. PELLICAM CASSETTE SYSTEM
a. Is a plate and frame style holder which accepts both ultra thin and depth
type filters.
b. Has from 0.5 to 25 ft^ of filter area.
c. Has not been investigated thoroughly but has had some success in virus
concentration.
d. Its main application for cyst recovery may lay with the processing of
filter washings.
8- FILTERWASHIMG APPARATUS
a. This is a proposed device by DuWalle, 1982 from U. of W., for unwinding
the fibers ^rom the filter cartridge while repeatedly brushing and
squeezing them while in a bath solution.
b. Bath could contain either a surfactant or pH controlled solution.
c. Potential claims are as high as 75 percent extraction of cysts from the
fibers.
1. Gone from 7 to 1 nm porsity filter
2. Limited the rate of flow to 1/2 gallon/min
3. Limited the pressure head to 10 PSI
4. Have gone to polyproylene filters in lieu of orlon
TABLE 2: DETECTION METHODS
1. Immunofluorescence
a. nFA
METHOD
INVESTIGATORS)
Riggs, CSDHS Lab, Berkley, CA
1983
Good prep.,
Cross Rx
RESULTS
b. I FA
Sauch, EPA-Cincinnati
Riggs, CSDS
Still under study
c. Monoclonal Antibodies Riggs, CSDHS
Sauch, EPA-Cincinnati
(unpublished)
Still under study
2. ELISA Method
Hungar, 0. Hopkins MD, 1983 Feces samples only
3. Brightfield/Phase Contrast EPA Consensus method
Ongoing
-------
APPENDIX C: CONCENTRATING, PROCESSING,
nETECTING AND IDENTIFYING filARDIA CYSTS IN WATER
DETECTIOH METHODS
1.a. DIRECT FLUORESCENT ANTIBODY (DRA) TECHNIQUE
1. Riggs has produced a high titer purified immune sera to Giardia lamblia
cysts in guinea pigs and labeled it with Fluorecein isothio cyanate. Sera
is purified thru MH4OH and OEAE se^adex fractionation.
2. Obtained cross reactions with Chilonastix mesnili cysts but claims it can
be easily distinguished from Giardia by its smaller size.
l.b. INDIRECT FLUORESCENT ANTIBODY (IFA) TECHNIQUE
1. Sauch using IFA with immune sera from rabbits (unpurified). It is reacted
with commercially available fluorescent-labeled goat anti-rabbit gamma
globulin.
2. Some cross-reactions with certain algal cells.
1.e. MONOCLONAL ANTIBODIES
1. Using clones of hybridoma cell lines obtained by fusing mouse myeloma
cells with spleen cells from mice (BALB/c) immunized with G. lamblia
trophozoi tes.
2. Produced eight monoclonal antibodies evaluated by IFA against both trophs
and cysts.
a. 3/8 stained the ventral disk
b. 2 stained the nuclei
c. 2 stained cytoplasmic granules
d. 2 stained membrane components
3. Variability in staining may be due to differences in stages of encystment.
4. Preliminary results indicate nonoclonal ABs may give rapid and specific ID
of cysts.
5. Rx may be too specific, not reacting with all human forms of G. lamblia
may have to go to polyclonal ABs.
2. EL ISA METHOD
a. Hungar at John Hopkins (unpublished) has produced a detection method by
ELISA using a intact "sandwich" technique in 96-well microtiter plates.
b. Using antisera from 2 different animals (may present problem).
c. Need a minimum of 12 cysts/well for color Rx.
(C5
-------
APPENDIX D:
GIARDIASIS IN WASHINGTON STATE and
GIARDIA PREVALENCE IN COMMERCIALLY TRAPPED MAMMALS
The fiollouti-ng two aAticlei provide detail* about the Wcu> king ton
Atudy that Floyd Tsio&t and Ryion Plan de&cAibed to the group
during the conference (<&ec page 26) .
A further a/iticle, "GiardLLa Prevalence among 1 -to- 3-Vear-Old Children
in Two UaAhlngton State Counties," ii> available thn.ou.gh the American
Journal of Public Health (April, 1982, \Jol. 12, No. 4).
-------
APPENDIX iJ: c.i/UvUi/olS IN WASIIINCIUN STA'l'Li
United States Health Effects Research
Environmental Protection Laboratory
Agency Research Triangle Park NC 27711
Research and Development EPA-600/S1-82-016 Feb. 1983
&EPA Project Summary
Giardiasis in Washington State
Floyd Frost, Lucy Harter, Byron Plan, Karen Fukutaki, and Bob Holman
This research was initiated to
determine the potential for
transmission of giardiasis through
approved drinking water supplies in
Washington State. The project
consisted of five separate studies.
The first study, a parasitologies!
stool survey of commercially trapped
aquatic mammals, was conducted
during each trapping season from
1976 to 1979 and resulted in the
examination of 656 beaver stool
samples, 172 muskrat stools and 83
other animal stool samples. Positivity
for beaver was 10.8%, whereas
positivity for muskrat was 51.2%. No
Giardia was found in other trapped
mammals (nutria, mink, raccoon, river
otter, bobcat, coyote, lynx, or
mountain beaver).
In the second study, a follow-up of
human giardiasis cases identified
through medical diagnostic
laboratories, 865 Giardia infected
Washington State residents were
contacted and asked a series of
questions designed to identify likely
sources or possible risk factors for
infection. Two outbreaks were
identified which implicated domestic
drinking water as the source. Other
clusters of cases were linked to day
cars centers, backpacker excursions
or sites for drawing water on outings
and foreign travel. No excess of cases
was observed for customers of
surface drinking water supplies.
The third study was a case-control
study to identify risk factors for
giardiasis. This study included 349
laboratory-identified cases and 349
controls selected from directory
assistance listings. Factors which
appeared to place a person at
increased risk of giardiasis included
consumption of untreated water,
foreign travel (for adults) and
attendance at a day care center (for
children under age 10).
The fourth study examined water
filtering techniques for recovery of
Giardia cysts from drinking water
supplies. Initial application of the
technique recovered cysts from
several supplies not implicated in
giardiasis outbreaks; however,
laboratory testing of the technique
demonstrated very poor cyst recovery
using the recommended filter
application and analysis techniques.
Changes in the application and
analysis techniques (lower water
pressure, use of a continuous flow
centrifuge, different filter fiber
washing techniques, i.e., a 1 micron
filter) yielded order of magnitude
improvements in cyst recovery. As
few as 3000 cysts in 500 gallons of
water would be adequate for cyst
identification under conditions of low
to medium turbidity.
The fifth study was a stool survey of
one- to three-year old children in
Skagit and Thurston counties.
Children were randomly selected
from birth certificate listings and
parents were paid to submit 2 stool
samples for analysis. Overall
prevalence of infection was 7.1% for
the children surveyed. No differences
in the prevalence were found by
source of domestic water (surface
filtered, surface unfiltered, well or
spring).
This report was submitted by the
Washington State Department of
Social and Health Services, Office of
Environmental Health Programs, in
-------
APPENDIX D: GIARDIASIS IN WASHINGTON STATE
fulfillment of Grant No. R-805809
from the U.S. Environmental
Protection Agency. This report covers
a period from July 1, 1978 to April 1,
1981 and work was completed as of
December 31, 1981.
This Project Summary was
developed by EPA's Health Effects
Research Laboratory. Research
Triangle Park, NC, to announce key
findings of the research project that is
fully documented in a separate report
of the same title (see Project Report
ordering information at back).
Introduction
Although Giardia infections in man
'have been recognized for centuries,
waterborne transmission of this
parasite has only recently been
recognized as a major mode of
dissemination. Drinking water
contaminated with human waste was
thought to be the likely source of a
giardiasis outbreak in Aspen, Colorado
in 1966. Contamination of water by
aquatic mammal waste was thought to
be the likely source of outbreaks in
Camas, Washington (1976) and Berlin,
New Hampshire (1976). The latter
outbreaks were of particular interest to
water treatment engineers and public
health officials, since the treated water
met both coliform and turbidity levels
believed to protect against waterborne
disease outbreaks. Furthermore, the
conditions which resulted in the Camas
outbreak were likely to occur commonly
throughout Washington State and
perhaps throughout much of the West.
Following the Camas outbreak of
April and May 1976, the Washington
State Department of Social and Health
Services (DSHS) together with the U.S.
Environmental Protection Agency (EPA)
began a series of investigations to
determine whether similar outbreaks
were occurring elsewhere in
Washington State and to estimate the
potential for future outbreaks. The
Camas outbreak was thought to be
related to Giardia infected beaver
residing in the watershed of the town's
surface water supply. Due to problems
with the Camas water filter system,
cysts (possibly excreted from beaver)
passed through the filter. They were
probably unaffected by the level of
chlorination used at the time of the
outbreak. The majority of Washington
State residents are served by surface
water supplies and many of these
supplies use chlorination as the only
means of disinfection. Since all of these
watersheds are frequented by beaver,
the presence of Giardia infected beaver
could lead to similar outbreaks.
Information was required on both the
potential for human exposure to Giardia
and the incidence of human illness. To
determine the extent of aquatic
mammal infection with Giardia, stool
surveys of commercially trapped
animals were initiated in the fall of 1976
and continued through spring 1980. To
assess the extent of human illness
resulting from giardiasis, a pilot human
case follow-up was initiated in 1977
and extended to a statewide human
follow-up in July 1 978. To identify risk
factors for human giardiasis, a
case-control study was initiated in
March 1979 and continued through
March 1980, when case follow-up was
also suspended. In July 1978 an
investigation was initiated to estimate
how frequently Giardia cysts could be
recovered from drinking water supplies
with the use of a large volume water
filtration technique developed by the
Health Effects Research Laboratory
(HERL), EPA. Due to problems with the
technique, this aspect of the study was
modified so that more effort was placed
on evaluating alternative methods for
cyst recovery. In September 1980 a
human stool survey of one-to-three-
year-old children was initiated to
determine whether a difference in
prevalence of infection existed between
areas served by surface water supplies
(Skagit county) and areas served by well
water supplies (Thurston county).
Conclusions
This project demonstrated a
widespread potential for waterborne
transmission of giardiasis in
Washington State. During the four
years of animal surveys, Giardia
prevalence in beaver ranged from 6% to
19% and in muskrat from 0% to 85%.
Infected beaver were found throughout
the state in both protected and
unprotected watersheds which provide
drinking water for Washington State
residents.
Statewide human giardiasis
surveillance efforts and follow-up
substantially increased the number of
reported giardiasis cases, identified two
outbreaks associated with domestic
drinking water supplies, two day care
center outbreaks, one outbreak
associated with foreign travel and
numerous smaller clusters of cases.
From the case-control study, foreign
travel, consumption of untreated water
and attendance at a day care center (fnr
children) were found to be significantry
more common among giardiasis cases
than among controls'. Among giardiasis
cases with foreign travel, only travel to
Third World countries was found to be
associated with giardiasis.
The human case follow-up revealed
that giardiasis follows a bimodal age
distribution affecting both young
children and young adults. Evidence of
secondary transmission was observed,
especially in households with young
children. No excess of cases wa<:
observed among customers of surface
water supplies, even after individuals
with other likely sources of infection
(homosexuals, those who consumed
untreated' surface water, day-care
center attendees, persons with a
history of foreign travel, and case
clusters with a likelycommon exposure)
were eliminated.
Results of the stool survey of one- to
three-year-old children generally
supported the findings of the
case-control study and the human case
follow-up. No difference in Giardia
prevalence was observed for children
served by deep well water supplies and
surface supplies. In both cases one- to
three-year-olds were found to have a
7.1% prevalence of Giardia. A
increased risk of infection was found for
children with exposure to untreated
surface water and for children with
more than two siblings between the
ages of three and ten. No increased risk
was found for children attending day
care centers,contradicting results of the
case-control study.
Environmental sampling to recover
Giardia from natural waters proved tQ
be disappointing. Of the 77 water filter
samples examined, only 5 werepositive
for Giardia and three of these were
taken in response to a reported outbreak
An examination of recovery efficiency
was begun early in the project to test the
filter both in the field and in the
laboratory. Initial recovery of one cyst out
of 30,000 cysts was followed by changes
in both the application and analysis
procedures. These changes (lower water
pressures, more agitation to remove
cysts from the filter fibers, and the use
of a Foerst centrifuge) resulted in
recovery of nearly 10% of the
experimentally added cysts.
Concentration techniques using
sucrose or zinc sulfate were examine^
but did not provide noticeable
improvements when used on filte-
samples.
D2)
-------
APPLMHX I): GIARDIASIS IN WASHINGTON STATE
The implications of these findings for
waterborne transmission of giardiasis
in Washington State are as follows: 1)
Giardia infection among aquatic
mammals in Washington is widespread
and includes animals in the most
remote and protected watersheds. 2)
Although recovery of cysts from water
implicated in an outbreak has usually
been possible, recovery of cysts from
other surface water was only
occasionally possible. Although animal
trapping results suggest that cysts
should be commonly found in surface
waters, the concentration of cysts
required for filter recovery Is seldom
observed. 3) With the exception of
several outbreaks, Washington's
surface water supplies were not
associated with an increased risk of
giardiasis or Giardia infection in their
customers. The suspected excess level
of disease in communities served by
surface water supplies was not
observed. Consumption of untreated
surface water, person-to-person
transmission (primarily among
children), and travel to Third World
countries were the most important risk
factors associated with giardiasis.
Recommendations
Waterborne giardiasis does not
appear to be a significant public health
problem in Washington State, despite
the widespread potential for water
supply contamination. The waterborne
outbreaks detected were associated
with operational problems (Leavenworth)
and with inadequate design (Boistfort)
of treatment plants. No outbreaks were
detected in either Tacoma or Seattle,
even though infected animals were
trapped from the watersheds of the
surface water supplies, and the only
treatment provided these water
supplies is chlorination.
In contrast, untreated surface water
does present a significant public health
problem. Consumption of untreated
water was recognized as a risk factor for
giardiasis in all age groups and was also
associated with Giardia infection
among stool survey participants.
Orion-wound filters proved to be
useful in recovering cysts from water
supplies implicated in a human
giardiasis outbreak but did not yield
useful information on water supplies
randomly selected. Laboratory
evaluation of filter analysis procedures
suggests that improvements in recovery
and reductions in cost can be achieved
by using an algal (Foerst) centrifuge
rather than the series of screens
recommended in earlier studies.
Results of the stool survey suggest
that water contamination may interact
with other risk factors by providing an
initial infection. The number of children
in a household appeared to be a risk
factor; however, the risk was only
increased among families with a history
of untreated water consumption.
Floyd Frost. Lucy Harter. Byron Plan, Karen Fukutaki, and Bob Holman are with the
Department of Social and Health Services, State of Washington, t)lympia. VJA
98508.
Walter Jakubowski is the EPA Project Officer (see below).
The complete report, entitled "Giardiasis in Washington State," (Order No. PB
83-134 882; Cost: $11.50. subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Health Effects Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
(D3
-------
APPENDIX D: GIARDIA PREVALENCE IN COMMERCIALLY TRAPPED MAMMALS
Giardia Prevalence in
Commercially Trapped Mammals
Floyd Frost, Byron Plan, Bill Liechty
Recent outbreaks of giardiasis have
been linked to Giardia contamina-
tion of municipal water supplies
(1,8,10). Human or animal con-
tamination of drinking water has
been implicated in most of the out-
breaks (4). Of particular interest to
water utility operators and water
supply engineers is the possible
animal contamination of water
supplies which are protected from
human contamination.
A giardiasis outbreak in Camas,
Wash., was thought to have re-
sulted from aquatic mammal con-
tamination of an otherwise pro-
tected water supply (8). Following
this outbreak, the Washington
State Health Services Division
undertook a series of aquatic
mammal surveys to estimate the
prevalence of Giardia infection in
Washington's wild beaver and
muskrat population and to deter-
mine if animal contamination of
other water supplies could occur.
Many Washington State water
supplies use chlorination as the
only treatment for surface water,
and since chlorination may not in-
activate Giardia cysts (3,6), there
was concern that a number of cities
were vulnerable to giardiasis out-
breaks.
Floyd Frost, M.Sc., Research Investigator;
Byron Plan, M.Sc., Research Micro-
biologist; Bill Liechty, M.Sc., Sanitary
Engineer, Department of Social and
Health Services, Office of Environmental
Programs, State of Washington, Olym-
pia, Washington. Research supported by
Health Effects Research Laboratory,
USEPA, Grant R805809. Correspond-
ence should be addressed to Floyd FroRt,
Office of Environmental Programs
D.S.H.S. LD-11 Olympia, Washington
D4) 98504
Background:
Giardia is a flagellated protozoan
parasite which inhabits the small
intestine of amphibians, birds and
mammals (9). In Washington state
it is the most commonly identified
human intestinal parasite. Infec-
tion in humans can occur after in-
gesting as few as 10 cysts (11). Im-
plicated modes of transmission are
water, hand to mouth transfer, and
possibly contaminated food (13).
Recently, waterborne transmission
has received much attention.
Twenty waterborne outbreaks of
human giardiasis were reported be-
tween 1971 and 1977, sixteen of
which were associated with drink-
ing untreated or minimally treated
surface water (4). Outbreaks which
affected a large number of people
occurred in Rome, New York -1975,
Camas, Washington -1976, and Ber-
lin, New Hampshire - 1976. In each
of these outbreaks, Giardia cysts
were recovered from the municipal
drinking water supply (4,8,10).
During the Rome outbreak,
Giardia cysts were recovered for the
first time from a municipal raw
water supply. Patent Giardia infec-
tions developed in Giardia-free
beagle puppies when fed sediment
collected from the Rome water sup-
ply, suggesting that the waterborne
cysts were infective for humans (4).
During the Camas and Berlin out-
breaks, cysts were recovered from
the raw and treated water and from
beaver (8,10). Three Giardia-
infected beaver were trapped in the
Camas watershed and one in the
Berlin watershed. Attempts to in-
fect beagle puppies with Giardia re-
covered from the Camas supply
failed because cyst deterioration oc-
Giardia Cyst
Cl«rdla Trophozoite
(Frontal & Lateral Vl«v)
Giardia Trophozoite
curred prior to administration. No
beagle studies were attempted dur-
ing the Berlin outbreak. The Giar-
dia contamination of the Camas
water supply generated special
interest because this watershed,
unlike the Rome or Berlin water-
sheds, was uninhabited by humans
and closed to public access. This
finding suggested that beaver could
function as reservoir hosts for Giar-
dia and, thus, be of epidemiologic
importance in human giardiasis.
This has recently been supported in
Colorado where two of three volun-
teers became infected after ingest-
ing beaver Giardia (5).
Journal of Environmental Health, V. 42
(5) 245-249.
March/April, 1980
Journal of Environmental Health
-------
Following the Camas outbreak,
statewide surveys of aquatic mam-
mals were begun to determine the
extent of Giardia infection among
Washington's aquatic mammals.
Much of the drinking water in
Washington originates from sur-
face sources. Furthermore, many
cities which obtain drinking water
from streams use chlorine as the
only method of treatment, provided
that strict watershed protection and
low turbidity levels can be main-
tained. Since chlorine may not be
effective in inactivating cysts (3,6),
and these watersheds often contain
good habitats for beaver and other
aquatic mammals, the risk of
human infection through contami-
nated drinking water may be signif-
icant.
Materials and Methods:
Commercial trappers were re-
cruited to provide stool samples
from kill-trapped animals. Those
who agreed to participate were
supplied with sampling kits con-
taining vials, mailing containers,
instructions on how the sample was
to be obtained, and a survey form.
The first year of the survey the vials
contained no fluid. During the sec-
ond and third years the vials con-
tained '2.5% formalin solution. The
survey form requested information
on the animal species, sex, age, date
sample was taken, and location
where the animal was trapped
(watershed, township/range/sec-
tion, county, nearest town). During
the third year of the survey, infor-
mation on the general health, fur,
body fat and injuries to the animal
was also requested. The trappers
collected the samples from the large
intestine or rectum of the animal
using a wooden stick included with
each kit, The sample was then
placed in the vial and mailed to the
State Public Health Laboratory.
Only one sample was taken per
animal. Time between trapping and
receipt in the lab was generally less
than ten days.
Trappers were encouraged to
submit samples from animals trap-
ped in municipal watersheds. Spe-
cial arrangements were made for
obtaining animals from protected
watersheds. During the first year,
only beaver samples were re-
quested. Beaver, muskrat, mink,
racoon and river otter samples were
requested during the second and
third years.
Once the stool samples were re-
ceived at the State Public Health
Laboratory, they were processed by
the formalin-ether technique (12).
This procedure was selected be-
cause it permitted the processing of
large numbers of samples without
requiring immediate analysis.
After a stool sample was pro-
cessed, the sediment was thoroughly
mixed in 1 ml of 2.5% formalin. An
aliquot of this mixture was imme-
diately removed and placed on a mi-
croscope slide, at which time it was
mixed with a drop of Lugols iodine
and covered with a 22mm x 22mm
coverslip. The entire coverslip was
examined at lOOx using a com-
pound microscope. Structures re-
sembling Giardia cysts or other
parasites were verified at 450x. All
parasites and ova seen were iden-
tified to genus and recorded during
the third year. Only Giardia was
recorded during the first two years.
Parasite abundance for each
species of protozoan was estimated
by counting the number of or-
ganisms encountered on five differ-
ent lOOx fields, averaged and mul-
tiplied by 169, the number of lOOx
fields seen on a 22mm x 22mm cov-
erslip. In each sample, a given
quantity, approximating one gram
of feces, was processed. Statistical
analysis was done using SPSS t-test
and a logit analysis program.
Results
During the three years of the
study, 704 fecal samples were ex-
amined. Parasites were found in all
species of animals from which sam-
ples were submitted; however, only
beaver and muskrat harbored
Giardia (Table I). The percentage of
Giardia -positive animals increased
each year, due to the detection of
infected animals in previously
negative counties and to a higher
prevalence of Giardia infections in
animals from previously positive
counties.
Giardia prevalence in muskrat3
was higher than in beaver for the
second and third years (p < .01).
Juvenile beaver were more often
found to be infected than were
adults (p < .01) during both the '77-
'78 and the '78-'79 trapping seasons.
Muskrat samples pooled for the '77-
'79 trapping seasons also showed a
higher positivity among juveniles
(p < .05).
When cyst density measures were
compared, the number of cysts per
coverslip was greater for beaver
than for muskrat (p < .05). This dif-
ference was due to many beaver and
no muskrat having extremely high
cyst counts. Cyst density compari-
sons for adults versus juveniles of
the same speices did not demon-
strate significant differences be-
tween age groups.
No significant differences were
detected in the prevalence of other
parasitic infections among
Table 1
Parasite Findings
Number trapped (Percent Giardia infected)
Animal
Parasites
1976/1977
1977/1978
1978/1979
Beaver
G.C.Tr
173 (6,3%)
177 (6.8%)
179 (19V.)
Muskrat
G.E.Ch.C,
Tr.N.Tc
1
17(36.2%)
115 (42 6%)
Nutria
C.Tr
1
2
5
Mink
Tr.N.Tc
5
7
Raccoon
C.N.Tc
4
24
River Otter
Tr
1
2
10
Bobcat
To
7
Coyote
To
2
Lynx
To
1
G= Giardia sp.
C= coccidia
E= Entamoeba muris
Ch= Chilomastix sp. To= Toxocara sp.
Tr» tremalode eggs Tc- Trichuria sp.
N= nematode larvae
Journal of Environmental Health
Vol. 42, No. 5
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Table 2
Parasite Associations of Beaver and Muskrat
Beaver Giardia Positive
(34 animals)
67.6% no other parasites
11.8% coccidia
11.8% trematode
8.8% coccidia, trematode
Giardia Negative
(145 animals)
57.9% no other parasites
19.3% coccidia
15.9% trematode
6.9% coccidia, trematode
Muskrat Giardia Positive
(49 animals)
18.4% no other parasites
22.4% E. muris
14.3% trematode
22.4% E. muris and other parasites
22.4% other trematode,
coccidia, nematode,
Chilomastix combinations
Giardia Negative
(66 animals)
45.5% no other parasites
10.6% E. muris
22.7% trematode
13.6% E. muris and other parasites
7.5% other trematode,
coccidia, nematode,
Chilomastix combinations
Table 3
Beaver and Muskrat Posltivity
By Month Trapped For 1978/79 Survey
Beaver Muskrat
Percent Percent
Month Examined Giardia Pos. Examined Giardia Pos.
Nov. 81 23.4 56 53.6
Dec. 78 16.7 34 38.2
Jan.-Oct. 20 10.0 25 24.0
Table 4
Animal Samples by Geographic Region
Season
Results
Region
West
Northwest
Southwest
East
76-77
POS.
2
1
6
2
NEG.
31
43
23
65
77-78
POS.
3
3
5
1
NEG.
28
72
19
47
78-79
POS.
7
13
7
7
NEG.
30
60
14
41
COUNTIES
WEST: Clallam, Grays Harbor, Kitsap, Mason, Pacific, Jefferson
EAST: Chelan, Columbia, Ferry, Garfield, Grant, Kittitas, Lincoln, Okanogan. Pend Oreille,
Spokane, Stevens, Walla Walla. Yakima. Adams, Asotin
NORTHWEST: King, Pierce, Skagit, Snohomish, Whatcom
SOUTHWEST: Clark, Cowlitz, Lewis, Skamania, Thurston
LOGIT ANALYSIS FACTOR
Year
Region given year
Residual
G'
16.2
18.9
3.1
DEGREES OF FREEDOM
2 p < .005
3 p < .005
March/April, 1980
JournnI of Environmental Health
Giarcfia-positive versus Giardia-
negative beaver. Differences were
observed for Gi'ardia-positive ver-
sus Giardia-negative muskrat in
the prevalence of other infections (p
< .01). A higher percentage of
Giardia-negative muskrat had no
other parasitic infection and rela-
tively few had multiple parasite in-
fections (Table II).
Most samples were received dur-
ing the trapping season (November
through February), which limited
the examination of seasonality of
Giardia cyst excretion to these
months. A downward trend in
Giardia positivity was observed for
both beaver and muskrat, by month
trapped (p < .01), with November
having the highest positivity (Table
III). The period January to October
primarily contains animals trapped
in January or February. Only rarely
were animal samples received after
March 1.
Sex of the animal was not shown
to be related to risk of Giardia infec-
tion for either beaver or muskrat. It
should be noted that age and sex
determinations were made by the
trappers. It is questionable whether
accurate sex determinations were
made for beaver (7).
The prevalences of Giardia in bea-
ver were compared by geographic
area. Muskrat were not included in
the analysis because of the small
sample size and higher prevalence
of positive stools. The state was di-
vided by counties into geographic
divisions: western counties border-
ing the ocean, northwest counties,
southwest counties and counties
east of the Cascade Mountains.
Logit analysis suggests that
positivity was not uniform over
these regions (p < .01) (Table IV).
Beaver from southwest and western
counties showed a higher preva-
lence of infection than did beaver
from Cascade or eastern counties.
Differences in prevalence were
also examined by level of protection
of the watershed. Three groups
were considered: 1) the Green and
Cedar River watersheds, 2) other
protected watersheds, and 3) areas
outside of protected watersheds.
Logit analysis revealed no differ-
ences in prevalence for these three
areas during the three years of the
study (Table V).
-------
Table 5
Giardla Positivity by Type of Area
Season
Results
Watershed
Cedar and
Other Restricted
Green River
Watersheds
Other
76-77
POS.
0
1
10
NEG.
19
9
134
77-78
POS.
0
1
11
NEG.
16
12
137
78-79
POS.
7
2
25
NEG.
22
7
116
LOGIT ANALYSIS FACTOR
G2
DEGREES OF FREEDOM
Year
17.9
2 p < .005
Watershed
.3
2 p < .1
Residual
5.5
4
Discussion
The investigation has deter-
mined that Gicirdia is a common in-
testinal parasite of beaver and
muskrat in Washington. The study
should not be considered a random
sample of beaver and muskrat be-
cause the manner in which samples
were obtained did not give equal
probability of inclusion for all ani-
mals in the state. If cyst passage for
these mammals is similar to human
cyst passage, the use of a single
stool sample per animal may bias
the results by underestimating the
true prevalence of infection. For
these reasons the prevalence esti-
mates may not indicate the true
prevalence of infection in aquatic
mammals but may be regarded as
an approximate minimum preva-
lence level. Nevertheless, the study
documents a widespread distribu-
tion of infection across the state and
indicates that the potential for
water contamination by aquatic
mammals exists throughout Wash-
ington.
The increased prevalence of Giar-
dia in beaver and muskrat observed
each year may have been the result
of true increases in Giardia positiv-
ity or the result of better or different
methods of parasite detection. As
stated earlier, sample collection
methods changed slightly between
the first and second years. Also, the
precise locations where animals
were trapped varied from year to
year, which may have contributed
to changes in prevalence. However,
logit analysis revealed that trap-
ping season was significant even
after adjusting for differences in
prevalence by region.
Some researchers have suggested
that sewage plays an important role
in maintaining infection of aquatic
mammals (5). The results of this
study and the Camas outbreak in-
vestigation (8) do not support this
contention. The finding of infected
animals in the Jones Creek/Boulder
Creek, Cedar River and Green
River watersheds suggests that bea-
ver can maintain the infection in-
dependent of human involvement.
The possibility that infected beaver
migrated from outside the water-
sheds (areas less protected) cannot
be ruled out, but the finding of in-
fected beaver at four different loca-
tions within the Cedar and Green
River watersheds, three of which
were separated from each other by
at least nine miles, suggests that
this was unlikely. Transmission
from a single infected beaver to
other beaver is a possibility, but
positive beaver were found in loca-
tions fed by separate drainages.
Beaver and muskrat were the
only animals identified as Giardia
infected. Previous authors (2,5) re-
port Giardia infected beaver and
muskrat. However, no reports are
available on how commonly wild
animals are infected or what host or
environmental characteristics pre-
dispose wild animals to infection.
This study found that host age was
related to finding cysts in the stool,
as juvenile beaver were found
positive 3.9 times more often.
Whether adults become free of the
infection, develop latent infections
or shed cysts in lower or more vari-
able levels cannot be answered from
these data. The density of cysts in
the stools presents a somewhat
more confusing picture. Beaver
show a large variance of cyst den-
sities but a low prevalence of infec-
tion. For muskrats this is reversed.
Implications of the geographic
distribution analysis is unclear.
Whether the higher prevalence in
west and southwest Washington
(Table VI) is related to animal
abundance, to a closer relationship
to human populations, or to other
factors cannot be answered. How-
ever, the finding of infected animals
in well-protected watersheds sug-
gests that human sewage is not
necessary to maintain infections
among wild beaver. It also suggests
that protected watersheds will not
insure pathogen-free water.
References
1. Ahtone, J. (1979), Giardiasis at a Forest
Service Camp. Proceedings of the
Thirty-Fourth Annual Meeting of the
International Northwestern Conference
on Diseases in Nature Communicable to
Man, August 20-22, 1979, Port
Townsend, Washington.
2. Bishop, A. (1934), The intestinal pro-
tozoa of a muskrat, Fiber (Ondatra)
zibethica, with a note upon Retor-
tamonas sp. from the guinea pig. Parasit.
26: 578-581.
3. Cerva, L. (1955), Resistence cyst Lamb-
lia intestinalis vuei zevnim faktonun.
Cesk Parasit. 2:17-21.
4. Craun, G.F. (1979), Waterborne disease
outbreaks in the United States. J. Enu.
Health 41:259-265.
5. Davies, R. & C.P. Hibler (1979), Animal
reservoirs and cross-species transmis-
sion of Giardia. In Waterborne Trans-
mission of Giardiasis. USEPA, Cincin-
nati, Ohio. pp. 104-126.
6. HofF, J. (1979),Disinfection resistanceof
Giardia cysts: origins of current con-
cepts and research in progress. In
Waterborne Transmission of Giardiasis.
USEPA, Cincinnati, Ohio. pp. 231-239.
7. Ingles, L.G. (1974), Mammals of
California. Stanford Univ. Press, p. 150.
8. Kirner, J.C., J.D. Littler & L A. Angelo
(1978), A waterborne outbreak of giar-
diasis in Comas, Washington. J. Am.
Water Works Assoc. 70:35040.
9. Levine, N.D. (1973),Protozoan Parasites
of Domestic Animals and of Man 2nd
Edition, Burgess Publ. Co., Minneapolis,
Minn.
Journal of Environmental Health
Vol 4?. Na 5
-------
10. Lippy, E.C. (1978), Tracing a giardiasis
outbreak at Berlin, New Hampshire. J.
Am. Water Works Assoc. 70:512-520.
11. Rendtorff, R.C. (1954), The experimen-
tal transmission of human intestinal
protozoan parasites. IV. Attempts to
transmit Endamoeba coli and Giardia
lamblia cysts by water. Am. J. Hyg.
60:327-338.
12. Ritchie, L.S., C. Pan, & G. Hunter III
(1953), A comparison of the zinc sulfate
and the formalin-ether (406th MGL)
technique. Med. Bull. U.S. Army Far
East 1:111-113.
13. Wolfe, M.S. (1978), Current concepts in
parasitology. New Eng. J. Med.
298:319-321.
Acknowledgements
The cooperation of Mike Thomiley of the
Washington State Game Department and
the State Trappers Association is greatly ap-
preciated. Our thanks for guidance and as-
sistance to Walt Jakubowski, USEPA; Bob
Holman, Janice Jernigan and Yvonne
Fichtenau, DSHS Public Health Laboratory.
D8)
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APPENDIX E:
PUBLIC INFORMATION
The ^oitoMing va>k gsioup, cmp&te. See pageA 59 through 6 7
faoh the fiuZl ti&poAX ofa the. Pubtlc InfioAmatxon ivoikgAoup.
-------
APPHNDIX li: PUBIJC INFORMATION
&EPA
Drinking the Water in the Backcountry
During the last few years, increasing numbers of
campers, backpackers, anglers and hunters have been
stricken with waterborne diseases because they drank
water straight from streams, springs or lakes. Even
though the water appears to be sparkling clean and pure,
it may contain microorganisms which cause disease.
One particular organism common in many waters is
Giardia Lambiia. This parasite has been found in many
wild and domestic animals; therefore, it can be present in
wilderness areas regardless of whether there are humans
in the area.
The organism is transferred between animals and
humans by means of excreted fecal material. If the
infected animal or human defecates in or near a stream
the organisms are then spread through the water.
Beavers are very prevalent in the transmission of
Giardia. Their aquatic habits insure a steady supply of
the parasites to the water. Since the organisms can
survive in water for at least two months, the problem is
not limited to particular times of the year or sections of
streams.
Drinking water containing a few of these parasites
causes giardiasis, a severe gastro-intestinal disorder
which results in acute diarrhea, vomiting and loss of
appetite. These conditions can result in serious
dehydration of the body which can be a problem if you
are in the wilderness.
"An ounce of prevention is worth a pound of cure," and
in the case of giardiasis the best prevention is not to
drink naturally occurring water regardless of how pure it
looks. This means that you must either carry all your
own water or disinfect the water before drinking it.
Of course, carrying your own water is not a good
alternative if you plan to be out for any length of time,
but several methods are available for making water safe
to drink. These are boiling, homemade disinfectants
and commercially prepared disinfectants. The use of
commercially available filters for water purification
is discouraged since most of the devices do not filter
out particles small enough to eliminate Giardia or other
smaller organisms.
Boiling kills Giardia, bacteria and viruses. Research has
shown that boiling water vigorously for one minute
effectively eliminates these hazards. Boiling remains
effective even at high altitudes. Highly turbid (cloudy)
water, however, requires longer boiling times, five
minutes being a suitable minimum.
The table below lists the various disinfectants available
and the recommended dosage per quart of water. The
use of saturated iodine (made by dissolving iodine
crystals in water) is not recommended because it does
not kill all of the Giardia organisms in cold water.
Remember, although it may be inviting to dip a cup of
water from a clear, fast flowing mountain stream, you
may regret it later. The best rule to follow is to disinfect
all water when in the back country.
1*E Braiclfich
Water Disinfection Methods
DISINFECTANT
Chlorine Tablets
Household Bleach
Iodine Tablets
2% Tincture of Iodine
Saturated Iodine
QUANTITY PER
QUART OF WATER
5 Tablets
4 Drops
2 Tablets
10 Drops
Not Recommended
WAITING TIME
BEFORE DRINKING
30 Minutes'
30 Minutes
20 Minutes*
20 Minutes
'When using tablets, the waiting time begins after the tablets are dissolved.
(El
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