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Notice to Readers: National Recreational Water Illness Prevention Week --- May 19--25, 2008

The week of May 19--25, 2008, marks the fourth annual National Recreational Water Illness Prevention Week. This yearly observance provides an opportunity for public health agencies to increase awareness of recreational water illness and promote healthy recreational water experiences.

Recreational water illness (RWI) is spread by swallowing, breathing, or having contact with contaminated water from swimming pools, water parks, interactive fountains, spas, lakes, rivers, or oceans. The most commonly reported RWI is diarrhea caused by pathogens such as Cryptosporidium, Norovirus, Shigella, Escherichia coli O157:H7, and Giardia. Children, pregnant women, and persons with compromised immune systems are at greatest risk for RWIs. Infection with Cryptosporidium can be life threatening in persons with weakened immune systems. Other RWIs include various skin, ear, eye, respiratory, and neurologic infections.

In 2007, state and local health departments across the country investigated more RWI outbreaks than ever before. This upsurge was driven by an increase in the number of reported RWI outbreaks caused by Cryptosporidium, a chlorine-resistant parasite, and was primarily associated with treated recreational water venues, such as pools, water parks, and interactive fountains. Although seven such RWI outbreaks caused by Cryptosporidium were identified in 2004 (1), CDC has received preliminary reports of 18 that occurred during 2007 (CDC, unpublished data, 2008) and expects to receive more as the 2007 count is finalized. Because Cryptosporidium is chlorine resistant, even a well maintained pool can transmit this parasite. Therefore, public health officials, pool operators, and beach managers should work together to educate the public regarding preventing RWIs by keeping Cryptosporidium and other pathogens out of all recreational waters, treated and untreated (e.g., oceans and lakes). RWI prevention guidelines for pool staff members are available at Suggestions for pool users are available at

To help promote healthy recreational water experiences, public health officials also can participate in development of the national Model Aquatic Health Code (MAHC). Currently, no complete pool code exists at the national level. In 2005, local, state, and federal public health officials and representatives from the aquatics sector met to develop a strategic plan to prevent RWIs, with the top recommendation calling for a national model code that would provide uniform guidelines for the design, construction, operation, and maintenance of treated recreational water venues. Although it will not provide a set of federal regulations, MAHC will give state and local agencies a tool with which to update their own codes. Information regarding participation in the development of MAHC is available at

Suggestions for how public health professionals can promote healthy swimming during National Recreational Water Illness Prevention Week are available at Additional information is available at


  1. CDC. Surveillance for waterborne disease and outbreaks associated with recreational water---United States, 2003--2004. MMWR 2006;55(No. SS-12):1--30.

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Date last reviewed: 5/15/2008


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