Cryptosporidia are small coccidian parasites that infect the mucosal epithelia of a variety of vertebrate hosts, including humans, affecting the health, survival, and economic development of millions of people and animals worldwide. Human infection is mainly caused by two species: (1) Cryptosporidium parvum—also prevalent in young livestock; can be transmitted from animals to humans (zoonotic transmission, particularly important in children), from person to person (‘urban’ cycle, due to faecal–oral spread), through contamination of public drinking-water supplies (which can produce...

Cryptosporidia are small coccidian parasites that infect the mucosal epithelia of a variety of vertebrate hosts, including humans, affecting the health, survival, and economic development of millions of people and animals worldwide. Human infection is mainly caused by two species: (1) Cryptosporidium parvum—also prevalent in young livestock; can be transmitted from animals to humans (zoonotic transmission, particularly important in children), from person to person (‘urban’ cycle, due to faecal–oral spread), through contamination of public drinking-water supplies (which can produce massive outbreaks) or food (prepared by a sick food handler), and nosocomially. (2) ...