Definition - What does Cryptosporidium mean?
Cryptosporidium is a microscopic parasite that causes the diarrheal disease cryptosporidiosis. The parasite and the disease are both commonly called "crypto." There are many different species of crypto that infect animals and some of these also infect humans. The parasite can be spread in different ways, but the most common is through drinking water or recreational water. It is a leading cause of waterborne disease among humans.
Safeopedia explains Cryptosporidium
The crypto parasite has a protective shell, which allows it to survive outside of a host body for long periods of time. The shell also makes it more resistant to disinfection. Cryptosporidium enters into the body and travels through the small intestine into the large intestine where it burrows into the walls of the intestines. This typically causes a short bout of diarrhea in the host. The disease, most often, does not require medical treatment as those infected will typically recover if they have a healthy immune system. The easiest way to treat diarrhea is to keep well hydrated until the immune system recovers.