Swimming-associated cryptosporidiosis

In July and August 1988, an outbreak of gastroenteritis affected 44 of 60 (73%) persons from 5 separate swimming groups who had used the same swimming pool in Los Angeles. Cryptosporidium was identified in 5 of 8 (63%) stool specimens, and the clinical picture was consistent with Cryptosporidium infection. Resistance of Cryptosporidium to chlorine, an inadequately maintained pool filtration system, repeated exposure to pool water, and possible continuing pool contamination may have contributed to ongoing transmission. Cryptosporidium should be considered a potential etiologic agent of gastroenteritis associated with recreational water use.