Cryptosporidiosis is an intestinal disease caused by the parasite Cryptosporidium. Symptoms include nausea, abdominal pain and diarrhea. Infection usually occurs when a person consumes water or food that has been contaminated with infected feces. This can occur from swallowing water from swimming pools, lakes and rivers. Infection can also spread from one person to another. There is no specific treatment except rehydration when indicated.