Cryptosporidiosis is caused by Cryptosporidium, a protozoa infection that usually infects the gastrointestinal tract. The most common symptom is diarrhea along with cramping abdominal pain, especially in the right side. The diarrhea can be profuse and watery. Infection can also cause loss of appetite and vomiting.

In people whose immune systems aren't compromised, infection is either without symptoms or symptoms go away on their own, usually in 30 days. However, in young children and immunocompromised adults, infection can cause severe and lengthy illness.

Diagnosis is made by the identification of the parasite in fecal smears or by intestinal biopsy. Cryptosporidiosis has recently been added to the list of infections that must be reported by doctors and other health-care providers to the New York City Department of Health.

The primary way of getting infected is person to person via the fecal-oral route. Those at highest risk are young children, especially those in day care, those who engage in oral-anal sex, and close personal contacts of infected patients. Some outbreaks have been traced to water supply systems.

Cryptosporidiosis was first found in a human in 1976. Before that, cryptosporidiosis was thought to only infect animals and was considered a veterinary problem. Around 1983, the number of human cases began to rise.

Increases in HIV infection have led to a rise in cryptosporidiosis infection. For a person living with HIV, cryptosporidiosis may cause dangerous dehydration and malnutrition. Diarrhea leads to dehydration, and your body can't function without maintaining adequate levels of water.

There are no approved treatments for cryptosporidiosis. The drug paromomycin (Humatin) has commonly been used as a treatment, but a recent study found that the drug did not work. A very promising new treatment is the drug nitazoxanide (NTZ). This drug is available through an expanded access program for people with cryptosporidiosis. Call Sandy Faulkner at Unimed, (800) 864-6330 extension 3032.

Azithromycin (Zithromax) is another possible treatment. An special intravenous formulation of azithromycin is available through a treatment IND program for people who have failed or can't take other treatments. Call Premier Research at (800) 742-3029 for more information.

Symptoms of cryptosporidiosis include abdominal cramping, especially in the right side, nausea, and diarrhea lasting up to 21 days. Treatment for the symptoms can include Immodium, octreotides or opiates for the diarrhea. Hyperimmune bovine collostrum is being tested as a means to increase the body's production of natural immunoglobulins used in fighting crypto. Total parenteral nutrition, or intravenous feeding is sometimes recommended to replace nutrients.

High fat foods should be avoided as they are hard to digest and increase diarrhea. Foods containing lactose - dairy products such as cheeses, milk, and ice cream - produce similar effects.

Handwashing, especially after using the bathroom and during food preparation, is crucial in preventing the spread of crypto, as well as hepatitis and other infections. Safe sex practices reduce the risk of crypto. Boiling all drinking water for at least 1 minute is recommended for people with less than 200 T4 cells. This has been shown to kill the cryptosporidia that causes diarrhea.

Other treatments for cryptosporidiosis are under investigation. For information about these studies call the Network at (800) 734-7104.

To report cases of cryptosporidiosis, and for more information about treatments, doctors and other health care providers can call the NYC DOH (at 212) 788-4204.