- Last Update On : 2013-01-08
Cryptosporidium is an extremely chlorine-tolerant intracellular protozoan parasite that causes diarrheal illness worldwide, including the United States. The incidence of reported cryptosporidiosis in the United States increased from 1.0 case per 100,000 population in 1999 to >3.0 cases in 2008 (Yoder JS, Beach MJ. Cryptosporidium surveillance and risk factors in the United States Exp Parasitol 2010;124:31--9). Fecal-oral transmission of Cryptosporidium can occur via ingestion of contaminated recreational water, drinking water, food, or via contact with infected persons or animals, most notably preweaned calves. The principal Cryptosporidium species that infect humans are C. parvum, which can be transmitted zoonotically or anthroponotically, and Cryptosporidium hominis (formerly known as C. parvum genotype I), which primarily is transmitted anthroponotically.
Groups at particular risk of infection include the immunocompromised, especially those with HIV infection, family m