Fig. 1.

Outline of the Cryptosporidium parvum life cycle [Adapted and modified from (Thompson et al., 2005)].

Ingested oocysts release sporozoites, which invade the ileum, developing into trophozoites and type I meronts, containing type I merozoites. Released type I Merozoites can become trophozoites themselves or develop into type II meronts, which release type II merozoites, these develop into undifferentiated gamonts. Gamonts differentiate into macrogamonts or microgamonts, the latter produces microgametes, which fertilise macrogamonts. Sporulation occurs within the host, releasing thick walled oocysts into the environment and thin walled oocysts, which auto-infect the same host organism.