CausesBy Mayo Clinic staff
Cryptosporidium infection begins when you ingest the cells of one of nearly a dozen species of the one-celled cryptosporidium parasite. The Cryptosporidium parvum (C. parvum) species is responsible for the majority of infections in humans.
These parasites then travel to your intestinal tract, where they settle into the walls of your intestines. Eventually, more cells are produced and shed in massive quantities into your feces, where they are highly contagious.
You can become infected with cryptosporidium by touching anything that has come in contact with contaminated feces. Methods of infection include:
- Swallowing or putting something contaminated with cryptosporidium into your mouth
- Drinking water contaminated with cryptosporidium
- Swimming in water contaminated with cryptosporidium and accidentally swallowing some of it
- Eating uncooked food contaminated with cryptosporidium
- Touching your hand to your mouth if your hand has been in contact with a contaminated surface or object
- Having close contact with other infected people or animals — especially their feces — which can allow the parasite to be transmitted from your hands to your mouth
If you have a compromised immune system from HIV/AIDS, you're more susceptible to illness from cryptosporidium than is a person with a healthy immune system. People with HIV/AIDS can develop severe symptoms and a chronic, persistent form of disease that may be difficult to treat.
Cryptosporidium is one of the most common causes of diarrhea in humans. This parasite is difficult to eradicate because it's resistant to many chlorine-based disinfectants and can't be effectively removed by many filters. Cryptosporidium can also survive in the environment for many months at varying temperatures, though the parasite can be destroyed by freezing or boiling.
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