|Points Of Contact
|Assistant to Director for Science
|Assistant to Director for Field Operations
|National Capitol Region
|Pacific West Region
Cryptosporidium as a cause of human illness has only been recognized since 1976.
The disease gained national attention in 1993 when an outbreak of
cryptosporidiosis affected over 400,000 people in Milwaukee. The source of this
outbreak was the city’s water treatment system.
People become infected when they inject the infective cysts of this
protozoan parasite. Disease symptoms usually include diarrhea, abdominal cramps,
nausea, and less frequently fever, headache, and vomiting. Persons with healthy
immune systems improve without medication. Those with compromised immune
systems, including AIDS patients, cancer patients undergoing chemotherapy,
transplant patients, the very young, and the elderly, may develop a severe,
long-lasting infection, with diarrhea, that persists for several weeks to months,
or even years.
Exposure to this infection can be minimized by:
- Washing hands after any possible contact with human or animal feces, and
before and prior to handling food.
- Avoiding drinking or accidentally swallowing water from rivers, lakes,
streams, swimming pools or jacuzzis.
- The most certain treatment to destroy Cryptosporidium is to bring water to
a rolling boil for one minute (Add an additional minute
for each 1,000 feet above sea level). Boiling will also destroy other
organisms causing waterborne disease.
- A far less reliable treatment is the use of portable water filters combined with disinfection. Some
claim to remove Cryptosporidium oocysts, but test protocols are not uniform in
the industry and many have not been tested in unbiased laboratories. Purchase
only from reputable dealers, and check product literature to ensure that the
filter is labeled according to filter manufacturing standards as at least an "Absolute" 1 micron filter, or one labeled as
meeting American National Standards Institute (ANSI/NSF) (formerly the National
Sanitation Foundation) International Standard #53 for "Cyst Removal"
followed by disinfection. Add 8 drops of
bleach or 20 drops of tincture of iodine per gallon of water and let stand for 30
minutes. No other filters are
reliable for removing Cryptosporidium.
For short trips, take a supply of water from home or from other treated
domestic sources. Due to the lack of labeling and manufacturing standards,
there is no assurance that bottled water is safer than public drinking water and
may require boiling also.
If you have any questions, please contact your nearest Regional Point of Contact,
park sanitarian or call WASO Public Health for more information.
Health Information, National Center for Infectious Diseases, Centers for Disease
Control and Prevention, Department of Health and Human Services.
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