From Our 2007 Archives
CDC Warns of Swimming Pool Health Risk
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Parasites Causing Diarrhea Can Spread in Pools, Water Parks; CDC Tells Swimmers, Pool Operators What to Do
Reviewed By Louise Chang, MD
July 26, 2007 -- The CDC announced today that swimming pools and water parks may need new technology -- and good hygiene from their patrons -- to prevent a diarrhea-causing illness that chlorine doesn't always stop.
Cryptosporidiosis is a gastrointestinal illness that can produce watery diarrhea for up to three weeks. It's caused by parasites and is spread through contact with contaminated feces.
The parasites can spread in swimming pools and water parks, even when the water has been treated with chlorine.
"To prevent outbreaks of cryptosporidiosis, change is needed in the way we build and operate the nation's disinfected recreational water facilities," states the CDC in a news release.
Today's CDC report shows that last year, five cryptosporidiosis outbreaks in Colorado, Illinois, Louisiana, South Carolina, and Wyoming were associated with swimming pools and water parks, including those with recommended chlorine levels.
All of the outbreaks were linked to swimmers.
In some cases, lab tests didn't show any signs of the cryptosporidiosis-causing parasites in the pool water. The CDC traced those outbreaks by talking to patients and others in the community.
Swimming Pool Upgrade
The CDC recommends upgrading the disinfection process for pool water by adding extra chlorine and treating the water with ultraviolet radiation or ozone systems.
Pools and water parks should also post signs alerting patrons to any diarrhea outbreaks and urging patrons with current or recent diarrhea to stay out of the water.
But the CDC says swimmers also need to help by following these tips:
The report appears in the CDC's Morbidity and Mortality Weekly Report.
SOURCES: CDC, Morbidity and Mortality Weekly Report, July 27, 2007; vol 56: pp 729-732. News release, CDC.
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