CDC Warns of Swimming Pool Health Risk

Parasites Causing Diarrhea Can Spread in Pools, Water Parks; CDC Tells Swimmers, Pool Operators What to Do

Medically Reviewed by Louise Chang, MD on July 26, 2007
From the WebMD Archives

July 26, 2007 -- The CDC announced today that swimming pools and water parksmay need new technology -- and good hygiene from their patrons -- to prevent adiarrhea-causing illness that chlorine doesn't always stop.

Cryptosporidiosis is a gastrointestinal illness that can produce waterydiarrhea for up to three weeks. It's caused by parasites and is spreadthrough contact with contaminated feces.

The parasites can spread in swimming pools and water parks, even when thewater has been treated with chlorine.

"To prevent outbreaks of cryptosporidiosis, change is needed in the waywe build and operate the nation's disinfected recreational waterfacilities," states the CDC in a news release.

Today's CDC report shows that last year, five cryptosporidiosis outbreaksin Colorado, Illinois,Louisiana, South Carolina, and Wyoming were associated with swimming pools andwater 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 thecryptosporidiosis-causing parasites in the pool water. The CDC traced thoseoutbreaks by talking to patients and others in the community.

Swimming Pool Upgrade

The CDC recommends upgrading the disinfection process for pool water byadding extra chlorine and treating the water with ultraviolet radiation orozone systems.

Pools and water parks should also post signs alerting patrons to anydiarrhea outbreaks and urging patrons with current or recent diarrhea to stayout of the water.

But the CDC says swimmers also need to help by following these tips:

  • If you've got diarrhea, don't get in the water until two weeks after thediarrhea ends.
  • Avoid swallowing pool water.
  • Practice good hygiene. Wash your hands after using a restroom or changingdiapers.
  • Shower before getting into the water.
  • Report fecal contamination to pool operators.

The report appears in the CDC's Morbidity and Mortality WeeklyReport.

Show Sources

SOURCES: CDC, Morbidity and Mortality Weekly Report, July 27, 2007; vol 56: pp 729-732. News release, CDC.

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