Cryptosporidium is a protozoan parasite that infects the epithelial cells of the small intestine causing diarrheal illness in humans. It has a worldwide distribution and is considered an emerging zoonotic parasite with reservoirs in cattle, domestic animals and in fecally contaminated environments. 1 Transmission via the fecal-oral route is due to the ingestion of Cryptosporidium oocysts through the consumption of contaminated food or water and through direct person to person or animal-to-person contact. These small-sized oocysts (4-6 μm) are highly resistant to common household disinfectants. 2,3 Diarrhea caused by Cryptosporidium is usually mild and self-limited in patients with good immunity.