Cryptosporidiidae

Eucoccidian apicomplexan sporozoa; from intestinal or respiratory spaces of teleosts, amphibia, reptiles, birds, and mammals; on the luminal surface of epithelial; life cycles of all members of the genus are homoxenous, and oocysts contain four naked sporozoites; on ingestion, sporozoites exit through a suture along one side of the oocyst wall and enter intestinal epithelial cells; two or three types of meronts occur - with one capable of recycling and causing autoinfection; the last generation of meronts form macrogametes and microgametocytes, the latter producing 16 non-flagellated microgametes; fertilized zygote produces a resistant oocyst wall; sporogony endogenous and fully sporulated oocysts are liberated in faeces; oocysts subspherical to ellipsoidal, and most about 4-8 µm long; about 20% of the oocysts of some species produce a thin, incomplete oocyst wall composed of a series of membranes from which sporozoites can excyst in situ and establish new infections by autoinfection.