Cryptosporidium enteritis

Alternative names

Cryptosporidium enteritis is an infection of the small intestine that is caused by the parasite cryptosporidium. The main symptom is diarrhea.

Causes, incidence, and risk factors

Cryptosporidium has recently been recognized as a worldwide cause of diarrhea in all age groups - yet its major impact has been among individuals with weakened immune systems (including people with HIV or AIDS) and transplant recipients. In such people, this diarrheal infection is not just bothersome but can lead to severe and potentially life-threatening wasting and malnutrition.

The major risk factor is ingestion of fecally contaminated water. Young children, animal handlers, people with close contacts of infected individuals, and men who have sex with men are at higher risk.

Outbreaks have been linked to drinking from contaminated public water supplies, drinking unpasteurized cider, and swimming in contaminated pools and lakes.


  • Watery diarrhea several times a day  
  • Abdominal cramping  
  • Nausea  
  • Malaise  
  • Malnutrition and weight loss (in severe cases)

Signs and tests

  • Stool ova and parasites exam  
  • Intestinal biopsy (rare)


There is no reliable treatment for cryptosporidium enteritis - certain agents such as paromomycin, atovaquone, nitazoxanide, and azithromycin are sometimes used but they usually have only temporary effects. Currently, the best approach is to improve the immune status in immunodeficient individuals, for example, by using antiviral therapy in patients with AIDS and supportive treatment for symptoms.

AIDS specialists and patient activists may provide additional information on the latest treatments and on medications and alternative treatments which may provide some relief.

Expectations (prognosis)
The infection will clear up in healthy people, although it may last up to a month. In immunosuppressed individuals, prolonged diarrhea with wasting and malnutrition may result.


  • Severe malabsorption (inadequate absorption of nutrients from the intestinal tract)  
  • Wasting syndrome  
  • Biliary tract involvement such as cholangitis, cholecystitis  
  • Hepatitis  
  • Pancreatitis

Calling your health care provider
Notify your health care provider if you develop watery diarrhea that does not resolve within several days, especially if you are immunosuppressed.

Proper sanitation and hygiene are important measures in the prevention of this illness. Boiling tap water for at least 1 minute is recommended for individuals who are immunosuppressed. Certain commercially available water filters can also reduce risk by filtering out the eggs of the cryptosporidium organism.

Johns Hopkins patient information

Last revised: December 8, 2012
by Armen E. Martirosyan, M.D.

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