Cryptosporidium species are protozoan parasites which were first discovered in 1907. There are more than 20 Cryptosporidium species which infect a wide range in animal species, including humans.
Life Cycle: Cryptosporidium have a direct life cycle involving a single host. Oocysts containing four naked infectious sporozoites are shed in the feces of an infected host, contaminating the surrounding environment. Once ingested by a new host, both asexual and sexual stages develop in the intestinal epithelium, leading to the release of new oocysts.
Transmission: Cryptosporidium can be transmitted via respiratory secretions, in addition to the fecal-oral route. The new host inhale aerosolized droplets.