Prevalence of parasites in fecal material from chlorinated swimming pools--United States, 1999.

As a result of the 1998 outbreak of infection with the chlorine-sensitive pathogen Escherichia coli O157:H7 at a waterpark in Georgia, many public health departments updated their guidelines for disinfecting pools following a fecal accident. Many of these guidelines recommended treating all fecal accidents as if they contained the highly chlorine-resistant parasite Cryptosporidium parvum, generally resulting in hyperchlorination and pool closures of up to a day. To determine whether fecal accidents commonly contained Cryptosporidium, the prevalence of this parasite and the moderately chlorine sensitive parasite Giardia intestinalis was assessed by asking swimming pool operators throughout the United States to collect formed stools from fecal accidents in their pools. This report summarizes the results of this study and provides recommendations for disinfecting pools following fecal accidents.