Definition By Mayo Clinic staff:
Cryptosporidium infection (cryptosporidiosis) is a gastrointestinal disease whose primary symptom is diarrhea. The illness begins when the tiny cryptosporidium parasites enter your body and travel to your small intestine. Cryptosporidium (krip-toe-spo-RID-ee-um) then begins its life cycle inside your body — burrowing into the walls of your intestines and then later being shed in your feces.
In most healthy people, a cryptosporidium infection produces a bout of watery diarrhea and the infection usually goes away within a week or two. If you have a compromised immune system, a cryptosporidium infection can become life-threatening without proper treatment.
You can help prevent cryptosporidium by practicing good hygiene and by avoiding drinking water that hasn’t been boiled or filtered.