Cryptosporidiosis is an illness caused by the parasite, Cryptosporidium. The condition is most commonly associated with watery diarrhea. Other signs and symptoms may include dehydration, weight loss, stomach cramps, fever, nausea and/or vomiting. 

Cryptosporidiosis occurs when the parasite enters the body, often through contaminated food and water or because of poor handwashing hygiene. Although cryptosporidiosis can affect all people, young children, pregnant women and people with severely weakened immune systems (i.e. those with AIDS; cancer and transplant patients who are taking certain immunosuppressive drugs; and those with inherited diseases that affect the immune system) are likely to develop a more serious illness. Medications such as nitazoxanide have been used to treat diarrhea in both adults and children. However, most people who have healthy immune systems will recover without treatment.