While the Crypto parasite is very small, it can normally be filtered out by municipal water-filtration systems. However, concerns arise when contaminant loads become very high, which may allow crypto to get through the water treatment process. This parasite is common in healthy pigs. It can cause severe diarrhea in humans on rare occasions. Usually it only occurs in people living in close contact with pigs and those who practice poor hygiene or who have other underlying disease conditions.
Humans are very resistant to infection, especially in industrialized countries.
Balantidium has not been a public health concern in industrialized countries that raise pigs intensively. Summary Human infection with pig parasites is uncommon in Canada. Unless people handle pig manure, have poor personal hygiene, drink untreated surface water or have an impaired immune function, they are at minimal risk for contracting any of these infections. People working inside pig units rarely become infected because the infection sources are not easily passed from pigs to humans. By comparison, our household pets also harbor many parasites, including roundworms, Giardia and Cryptosporidia, yet rarely do we become ill.