Cryptosporidium species are apicomplexan parasites that infect the microvillus border of the gastrointestinal epithelium of a wide range of vertebrate hosts, including humans.Infected individuals show a wide spectrum of clinical presentations, but the pathogenicity of Cryptosporidium varies with the species of parasites involved and also the type, age, and immune status of the host. Cryptosporidium infections are associated with only acute, self-limiting illness while in animals or individuals who are immune-suppressed; the infection is frequently chronic and can eventually be lethal....