Active, multisite, laboratory-based surveillance for Cryptosporidium parvum

Cryptosporidium parvum leaped to the attention of the United States followi ng the 1993 outbreak in Milwaukee, Wisconsin, which sickened 400,000 people . Other outbreaks in the United States have been associated with drinking a nd recreational water, consumption of contaminated foods, contact with anim als, and childcare attendance. Despite its public health importance, the nu mber of people who become infected each year is not known. In 1997, active surveillance for C. parvum was added to the Foodborne Diseases Active Surve illance Network (FoodNet), a collaborative effort among the Centers for Dis ease Control and Prevention, selected state health departments, the U.S. De partments of Agriculture and Food and Drug Administration. During the first 2 years of surveillance, 1,023 laboratory-confirmed cases of cryptosporidi osis were detected in FoodNet (Connecticut, Minnesota, Oregon, and selected counties in California, Georgia, Maryland, and New York). The annual rate per 100,000 persons was 2.3. Sixteen percent of case-patients were hospital ized. A seasonal increase in case detection was noted in late summer among persons less than 15 years of age. These data represent the first active mu ltistate ascertainment of laboratory-confirmed cryptosporidiosis cases and provide useful information on the burden of disease in the United States.