Cryptosporidiosis
Cryptosporidiosis is a diarrhea-producing intestinal infection caused by the one-celled parasite Cryptosporidium parvum.
Cryptosporidium infects people and many species of animals throughout the world. The infection is acquired by ingesting fecally contaminated water or food or by touching the mouth after having contact with soil, a person, or an item that has been contaminated with the organism. Cryptosporidiosis is a common cause of diarrhea among children living in developing areas where sanitation is poor. It also occasionally occurs among people who travel to these areas. People with a weakened immune system, particularly those with AIDS, are prone to infection with Cryptosporidium and are more likely to have severe disease.
The egg cysts (oocysts) of Cryptosporidium are very hardy and are frequently present in surface water in the United States. Many farm animals also harbor the organism. Cryptosporidium is not killed by freezing or by the usual levels of chlorine in swimming pools or drinking water.
Symptoms and Diagnosis
Symptoms begin 7 to 10 days after infection and consist mainly of cramps and watery diarrhea. Vomiting, fever, and weakness also may occur. The severity of the diarrhea varies from mild to severe (as much as 3 to 4 gallons of watery stool per day in people with AIDS).
To diagnose cryptosporidiosis, a doctor takes a stool sample for examination.
Prevention and Treatment
Prevention of cryptosporidiosis involves proper sanitation and hand washing, particularly in health care facilities and day care centers and after contact with soil, animals, or infected people. When public health departments discover a municipal outbreak of the disease, they typically advise people to boil drinking water (including water for toothbrushing and food washing), to eat only cooked foods, and to avoid unpasteurized milk and juice. Bottled water cannot be presumed to be safe. Tap water filters that use reverse osmosis or have the words "absolute 1 micron" or "tested and certified by NSF Standard 53 for cyst removal/reduction" are effective. Other types of filters may not be.
People with a healthy immune system typically recover on their own. A person with severe diarrhea may require treatment with oral or intravenous fluids and antidiarrheal drugs such as loperamide. No drugs have been found that kill Cryptosporidium in people with diarrhea. In people with AIDS, treatment with antiretroviral therapy can improve immune function and relieve diarrhea caused by Cryptosporidium; however, they may remain permanently infected.
| 
