Active, multisite, laboratory-based surveillance for Cryptosporidium parvum.

Abstract

Abstract. Cryptosporidium parvum leaped to the attention of the United States following the 1993 outbreak in Milwaukee, Wisconsin, which sickened 400,000 people. Other outbreaks in the United States have been associated with drinking and recreational water, consumption of contaminated foods, contact with animals, and childcare attendance. Despite its public health importance, the number of people who become infected each year is not known. In 1997, active surveillance for C. parvum was added to the Foodborne Diseases Active Surveillance Network (FoodNet), a collaborative effort among the Centers for Disease Control and Prevention, selected state health departments, the U.S. Departments of Agriculture and Food and Drug Administration. During the first 2 years of surveillance, 1,023 laboratory-confirmed cases of cryptosporidiosis 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 hospitalized. 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 multistate ascertainment of laboratoryconfirmed cryptosporidiosis cases and provide useful information on the burden of disease in the United States.

Global Distribution, Public Health and Clinical Impact of the Protozoan PathogenCryptosporidium

“…Most cryptosporidiosis outbreaks in the USA are caused by C. hominis , and this species is often reported as the primary cause of cryptosporidiosis in this country [143, 144]. However, outbreaks account for only 10% of the overall cryptosporidiosis cases, and there are still few data on the species causing sporadic cases [145] (Table 2). The highest incidence of cryptosporidiosis in the USA has been found in the upper Midwest States [146].…”

Is drinking water a risk factor for endemic cryptosporidiosis? A case-control study in the immunocompetent general population of the San Francisco Bay Area

“…Even though cryptosporidiosis is a reportable disease, limited data are available on the routes of endemic transmission and on accurate incidence rates of cryptosporidiosis, especially in the immunocompetent population. The few studies that have utilized information on cases detected via surveillance [17-19] have presented only a partial picture of the risk of cryptosporidiosis because of incomplete case ascertainment. The principal reason for this is that the disease is under-reported by physicians and laboratories and it is frequently under-diagnosed [20].…”

Evidence Supporting Zoonotic Transmission of Cryptosporidium spp. in Wisconsin

“…To date, U.S. studies identifying the causative species of cryptosporidiosis have been limited to outbreaks and sporadic cases occurring in AIDS patients from urban areas (34). While it is interesting that most cryptosporidiosis outbreaks in the United States are caused by C. hominis, outbreaks have been estimated to account for only 10% of the overall number of cryptosporidiosis cases (5). The anthroponotic C. hominis species might also predominate in urban environments, where human contact is more frequent than contact with animals, such as cattle.…”