Figure 1: Life cycle of Cryptosporidium in the enterocyte. Following oocyst ingestion by a host, and excystation, the sporozoites are released and parasitize epithelial cells of the gastrointestinal tract. In these cells, the parasites undergo asexual multiplication (schizogony or merogony) and then sexual multiplication (gametogony), producing microgamonts and macrogamonts. Upon fertilization of the macrogamonts by the microgametes, oocysts develop and sporulate in the infected host. Two different types of oocysts are produced: the thick-walled, which is commonly excreted by the host, after sporogony, and the thin-walled oocyst, which is primarily involved in autoinfection. Putignani and Menchella, 2010.