What is Cryptosporidiosis?

Cryptosporidiosis, or crypto, is a disease caused by parasitic infection by the protozoan Cryptosporidium. The parasite infects the epithelial tissue, or lining, of the small intestine, usually resulting in diarrhea. Cryptosporidiosis is spread through oral-fecal contact, often through the water supply. The infection is typically not serious, but it can be deadly to people with compromised immune systems, such as those with acquired immuno-deficiency syndrome (HIV/AIDS). Cryptosporidiosis is treated by addressing its symptoms, through pain management, rehydration, and electrolyte balance.

The Cryptosporidium parasite is closely related to the parasites that cause malaria and toxoplasmosis. There are many species of Cryptosporidium that can infect humans, including C. canis, C. felis, C. hominis, C. meleagridis, C. muris, and C. parvum. Parasitic infection is transmitted by microbial cyst, a dormant stage in the life cycle of the parasite. Once inside the intestine of the host, the parasite excysts an enters an active stage.

Cryptosporidiosis is most often transmitted through the water supply, but food and earth can also be contaminated. Anything that has been contaminated with the feces of an infected human or animal, and consumed by another can spread the parasite, as well as direct contact with the feces of an infected person or animal, such as when changing a diaper or cleaning up after domestic animals. Undercooked food, and water that has not been sufficiently disinfected, used either for drinking or in swimming pools, presents a risk. Cryptosporidium is resistant to chlorine and other disinfectants, and hence can remain in the water even after chemical treatment. Boiling is the most reliable method of making sure water is safe to drink.

As few as two Cryptosporidium organisms may be responsible for parasitic infection in an individual. Symptoms first appear about a week after infection, and can include watery diarrhea, abdominal cramping, fever, nausea, vomiting, dehydration, and weight loss. In otherwise healthy individuals, cryptosporidiosis can last anywhere from a few days to a month. Some infections are asymptomatic, and symptoms vary in severity among those infected. Even when there are no symptoms, or after any symptoms have subsided, infected individuals can still spread the disease to others.

In people with compromised immune systems, as well as the very young and the very old, cryptosporidiosis can be a very serious disease. In some cases, Cryptosporidium can cause a lifelong infection. There is no cure for the disease if it does not resolve on its own, but it can be managed through diet and fluid replacement. Oral rehydration is usually sufficient, but intravenous hydration is necessary for some patients. Immune-boosting therapies such as oral probiotics, which promote the growth of healthy bacteria, are sometimes helpful in resolving cryptosporidiosis.