Cryptosporidium parvum

Members of the Cryptosporidium family are parasites of the intestinal tracts of fish, reptiles, birds and mammals. Cryptosporidium found in humans is referred to as Cryptosporidium parvum.

Cryptosporidium is a small parasite that lives on the surface of the cells lining the small intestine, reproduces asexually and oocysts are passed in the faeces. Transmission of the infection occurs via the oocysts and many human infections have been traced to the contamination of drinking water with oocysts from drainage of agricultural land.

In most people infected with cryptosporidiosis the infection causes short term, mild diarrhoea. Since such symptoms are associated with a number of ailments, infected individuals may not seek medical treatment and the infection may subside on its own. It is therefore, difficult to say how many people are infected.

In people with compromised immune systems, this parasite can cause chronic diarrhoea; in severe cases the infected individual may produce up to 15 litres / day of stools and this may continue for weeks or months.