| Escherichia
coli O157:H7 and Drinking Water from Private Wells
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What is Escherichia coli O157:H7?
E. coli O157:H7
(Ee Koe-lie) is one of the hundreds of strains of the bacterium Escherichia
coli. Most strains are harmless and live in the intestines of healthy
humans and animals. However, this strain, O157:H7, produces a powerful
toxin that can cause severe illness. The bacteria can be found on a small
number of cattle farms and can live in the intestines of healthy cattle.
How can I become infected with E. coli O157:H7?
Eating meat, especially ground beef, that has not been cooked sufficiently
to kill E. coli O157:H7 can cause infection. Other known
modes of infection include:
- Eating
contaminated sprouts, lettuce, or salami;
- Drinking
unpasteurized milk or juice;
- Swimming in or drinking sewage-contaminated water.
Where
and how does E. coli O157:H7 get into my drinking water?
E. coli O157:H7
is most commonly found on a small number of cattle farms where the bacteria
can live in the intestines of healthy cattle. Millions of germs can be
released in a bowel movement from an infected human or animal. E. coli O157:H7
may be found in water sources such as private wells that have been contaminated
with feces from infected humans or animals. Waste can enter the water through
various ways, including sewage overflows, polluted storm water runoff, and
agricultural runoff.
What are the symptoms
of an E. coli O157:H7 infection?
E. coli O157:H7 infection often causes severe bloody diarrhea
and abdominal cramps. However, sometimes the infection causes nonbloody
diarrhea or no symptoms at all. Usually there is little or no fever,
and the illness goes away in 5-10 days.
In some persons, particularly children under 5 years of age and the elderly,
the infection can also cause a complication called hemolytic uremic syndrome
(HUS), which causes kidney failure. About 2%-7% of E. coli 0157:H7
infections lead to this complication. In the United States, HUS is the
principal cause of acute kidney failure in children.
What should I do if I
think I have an E. coli O157:H7 infection?
See your health care provider
to discuss your concerns. All persons who suddenly have diarrhea with blood
in it should have their stool tested for E. coli O157:H7.
How is an E. coli
O157:H7 infection diagnosed?
E. coli O157:H7
infection is diagnosed by detecting the germ in a stool sample. However,
most laboratories do not test for E. coli O157:H7. It is important
for your health care provider to request that the stool specimen be tested
for this organism.
What is
the treatment for E. coli O157:H7 infections?
Most people recover without antibiotics or other specific treatment
in 5-10 days. There is no evidence that antibiotics will improve the
course of disease. In fact, treatment with some antibiotics might
even increase the likelihood of kidney complications. Avoid all antidiarrheal
agents, such as loperamide (Imodium), and consult with your health
care provider.
How do I remove E. coli O157:H7 from my drinking water?
Heating water at a full boil for 1 minute (3 minutes if you
live in a high altitude) will kill or inactivate E. coli O157:H7.
Water should then be stored in a clean container with a lid and refrigerated.
Currently, there is no filter certified to remove bacteria
from water. This issue is currently being studied.
You may also disinfect your well; contact your local health
department for recommended procedures. Remember to have your well
water tested periodically after disinfection to make sure the problem does
not recur.
Revised Summer 2003
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