Health Education To Villages
Home Programmes Resources India Partners Site Map About Us Contact Us

Centers for Disease Control and Prevention
 CDC Home Search Health Topics A-Z
Foodborne and Diarrheal Diseases BranchLink Online to Foodborne and Diarrheal Diseases BranchCDC MenuSafe Water System Menu


BackFact Sheet

Preventing Cryptosporidiosis:

What is Cryptosporidium?

Cryptosporidium (krip-toe-spo-rid-ee-um), often referred to as "crypto," is a microscopic parasite that can live in the intestines of humans and animals. The parasite is protected by an outer shell that allows it to survive outside the body for long periods of time and makes it very resistant to chlorine disinfection.

How long after infection do symptoms appear?

Symptoms generally begin 2-10 days after being infected.

What are the symptoms of crypto?

Symptoms include diarrhea, loose or watery stool, stomach cramps, upset stomach, and a slight fever. Some people have no symptoms.

How long will symptoms last?

Symptoms will last about 2 weeks; you may seem to get better, then worse. Once you feel better, you continue to pass Cryptosporidium in your stool for up to 2 months. During this 2-month period you may spread the infection to others.

Am I at risk for severe disease?

If you have a severely weakened immune system, you are at risk for more serious disease. Your symptoms may be more severe and could lead to serious or life-threatening illness. Examples of persons with weakened immune systems include those with HIV/AIDS; cancer and transplant patients who are taking certain immunosuppressive drugs; and those with inherited diseases that affect the immune system.

If you have a severely weakened immune system, consult with your health care provider for additional guidance. You can also call the CDC AIDS HOTLINE toll-free at 1-800-342-2437. Ask for more information on cryptosporidiosis, or go to the CDC Internet site: 

What should I do if I think I have crypto?

See your health care provider.

How is an infection diagnosed?

Your health care provider will ask you to submit stool samples to see if you are infected. Because testing for crypto can be difficult, you may be asked to submit several stool specimens over several days. Because tests for crypto are not routinely done in most laboratories, your health care provider should specifically request testing for the parasite.

Can crypto be treated?

Not effectively. Most people with a healthy immune system will recover on their own. People who are in poor health or who have a weakened immune system are at higher risk for more severe illness. If you have diarrhea, drink plenty of fluids to prevent dehydration. Rapid loss of fluids due to diarrhea can be life-threatening in babies; parents should consult their health care provider about fluid replacement therapy options for babies. Antidiarrheal medicine may help slow down diarrhea, but consult with your health care provider before taking it.

How is cryptosporidiosis spread ?

  • By accidentally swallowing anything that has come in contact with the stool of a person or animal with crypto.
  • By swallowing water contaminated with crypto. A person can swallow a crypto oocyst (oh-oh-sist), the infectious stage of the parasite, by swallowing water from swimming pools, hot tubs, jacuzzis, lakes, rivers, springs, ponds, or streams contaminated with sewage or feces from humans or animals.
  • By eating uncooked food contaminated with crypto. Thoroughly wash with water all vegetables and fruits you plan to eat raw. See below for information on making water safe.
  • By accidentally swallowing crypto picked up from surfaces (i.e., toys, bathroom fixtures, changing tables, diaper pails) contaminated with stool from an infected person.

How can I prevent cryptosporidiosis?

  • Wash your hands with soap and water after using the toilet, changing diapers, and before eating or preparing food.
  • Avoid water or food that may be contaminated.
  • Wash and/or peel all raw vegetables and fruits before eating.
  • Avoid drinking water from lakes, rivers, springs, ponds, or streams unless it has been filtered and chemically treated.
  • During community-wide outbreaks caused by contaminated drinking water, boil drinking water for 1 minute to kill the crypto parasite and make the water safe to drink.
  • When traveling in countries where the water supply may be unsafe, avoid drinking unboiled tap water and avoid uncooked foods washed with unboiled tap water. Pasteurized fruit drinks are safe to drink, as are steaming hot coffee and tea.
  • Click here to find out how to choose bottled water that is also safe to drink.
  • In the United States, nationally distributed brands of bottled or canned carbonated soft drinks are safe to drink. Commercially packaged noncarbonated soft drinks and fruit juices that do not require refrigeration until after they are opened (e.g. those that can be stored unrefrigerated on grocery shelves) also are safe.
  • Avoid swimming in pools if you have crypto and for at least 2 weeks after diarrhea stops. You can pass crypto in your stool and contaminate water for several weeks after you no longer have symptoms. This has resulted in several outbreaks of crypto among pool users. Crypto can survive in chlorinated pools for several days.


This fact sheet is for information only and is not meant to be used for self-diagnosis or as a substitute for consultation with a health care provider. If you have any questions about the disease described above or think that you may have a parasitic infection, consult a health care provider.

 to Top


CDC Menu

Centers for Disease Control and Prevention
National Center for Infectious Diseases
Division of Bacterial and Mycotic Diseases
Foodborne and Diarrheal Diseases Branch


 The Mother and Child Health and Education Trust Programmes | Resources | India | Partners | Site Map | About Us | Contact Us top of page