ATLANTA -- A spike in outbreaks of cryptosporidiosis in 2006 has spurred the CDC to launch an initiative this summer to improve the safety of swimming pools and other recreational water facilities.
ATLANTA, July 30 -- A spike in outbreaks of cryptosporidiosis in 2006 has spurred the CDC to launch an initiative this summer to improve the safety of swimming pools and other recreational water facilities.
The CDC identified 18 cryptosporidiosis outbreaks in 2006, according to a report in the July 27 issue of Morbidity and Mortality Weekly Report. That compares with five outbreaks in 2003 and seven in 2004, the last two years for which there is complete data.
Contaminated water in recreational facilities is suspected in most, if not all, of the outbreaks. Although limited testing of implicated water sources failed to confirm the presence of Cryptosporidium, CDC investigators concluded that the epidemiologic findings "implicated contaminated recreational water as the source of the outbreaks."
Concerned lest the 2006 spike become a trend, the CDC has joined with public health officials and representatives of aquatic interests to launch the Healthy Swimming initiative to improve recreational water safety. Information on the initiative is available at http://www.cdc.gov/healthyswimming.
To reduce the risk of cryptosporidiosis associated with recreational water venues, the CDC recommends the following:
The general public:
Health care providers:
"A multifaceted approach for prevention of cryptosporidiosis in treated water venues must address operational, technological, and behavioral factors related to recreational water use," CDC investigators stated.
The MMWR report described five laboratory-confirmed cryptosporidiosis outbreaks involving recreational water exposure in 2006:
Unlike bacteria, Cryptosporidium oocysts are resistant to chlorine disinfection and can survive for days in treated recreational water facilities, the CDC authors noted.
The parasite, which has an incubation period of up to 12 days, is the leading cause of gastroenteritis outbreaks associated with treated recreational water venues, accounting for about 60% of outbreaks reported to the CDC during 1995-2004.
In four of the five cases described in the CDC report, available records reflected adherence to recommendations for disinfection and chlorination. The observation emphasized that "conventional chlorination and filtration of swimming pools and water parks are inadequate to control cryptosporidiosis and transmission of recreational water illness."
Improved disinfection technology that inactivates Cryptosporidium and greater public awareness of healthy swimming practices are two public health interventions that might reduce transmission of the parasite, the CDC investigators concluded.