Cryptosporidium is a protozoan that causes the disease known as Cryptosporidiosis, a type of diarrhea that plagues both humans and animals. Cryptosporidium has long been recognized as a cause of intestinal disease in cattle and sheep, but not in humans until 1976, and has been found in over 85% of the water supplies in the US since then. The species, Cryptosporidium parvum, is the cause of many outbreaks in the water supply of affluent nations, and only has been considered a health risk since 1993, when Milwaukee, Wisconsin, had numerous cases of diarrhea traced to contamination in the city’s water supply.
The microorganism is about 1/16th the size of a dust particle that floats in the air. It takes only ten organisms to cause an infection; and each generation can develop and mature in as little as twelve to fourteen hours. Huge numbers can colonize in the intestinal tract in just a few days. Therefore, it takes special filtering to remove them from the drinking supply since they are not killed by routine chlorination of water. However, boiling can kill them. Boiling water for one minute will kill most water-born pathogens, including hepatitis A. In an altitude of more than 6,500 feet, the water should be boiled for at least three minutes.
Within the intestinal cells, the parasite goes through all the stages of its life cycle, producing worms, called oocysts, which pass out of the body in the feces. Oocysts can survive outside the body for long periods of time, eventually finding their way back into drinking water and food.
Cryptosporidium muris is also transmitted via contaminated water supplies from farm animal waste. As with other Cryptosporidium species, it is most often found in day-care centers, where infection is directly related to improper washing after diaper changes. In healthy patients, infection is usually mild and of a short duration, but in the immunocompromised, illness can be more acute and severe. Symptoms include the following: abdominal discomfort, weight loss, fever, and nausea causing severe dehydration and electrolyte imbalances.