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What is it?

Cryptosporidiosis (krip-toh-spo-ri-dee-oh-sus) is an illness caused by microscopic, single celled parasites, Cryptosporidium. When the parasite enter the body, it lives in the intestine and is passed in the feces (stool). Cryptosporidium causes the diarrheal disease Cryptosporidiosis. It’s occurrence is worldwide.

How is cryptosporidiosis spread?

Cryptosporidium is shed in the feces of infected animals and humans. The illness can be acquired through animal-to-person or person-to-person transmission. Persons can become infected if they swallow contaminated food or water. Cryptosporidium oocytes (egg cysts) can survive outside the body for long periods of time. The oocysts are resistant to heat, cold and chlorine-based disinfectants.

You can become infected by:

  • ingesting contaminated drinking or recreational water
  • touching your mouth with contaminated hands
  • putting something in your mouth that has come into contact with the droppings of infected animals or stool of infected humans
  • eating raw or undercooked food that is contaminated, or
  • exposure to feces of an infected individual through sexual contact.

What are the symptoms of cryptosporidiosis?

Symptoms of cryptosporidiosis usually begin anywhere from 1 – 12 days (average of seven days) after becoming infected. The symptoms generally last 10 – 14 days, although occasionally they may last longer. The organism can continue to be excreted in the stool for several weeks after symptoms have resolved.
Persons infected with Cryptosporidium may have a variety of intestinal symptoms, including:

  • watery diarrhea or loose stool
  • stomach cramps or pain
  • dehydration
  • nausea
  • vomiting
  • low-grade fever, and
  • weight loss

Some people infected with Cryptosporidium may not have any symptoms. These asymptomatic individuals can still pass the disease on to others.
Cryptosporidium infection can be life-threatening for individuals with weakened immune systems, such as people with HIV/AIDS, those undergoing chemotherapy treatment or persons taking immunosuppressive medication.

How is cryptosporidiosis diagnosed and treated?

Cryptosporidiosis is usually diagnosed by examination of stool samples.
Most people with healthy immune systems will recover without treatment. Treatment of cryptosporidiosis usually involves treating the symptoms only. For example, persons with diarrhea should generally drink lots of liquids to avoid dehydration.

How can I protect myself and prevent the spread?

To prevent the spread to yourself or others, the following measures should be practiced:

  • Practice thorough hand washing with soap and warm water.
  • Use care when handling animal feces. Wear disposable gloves , then wash your hands.
  • Exclude children with diarrhea from daycares until the diarrhea stops.
  • Remove infected persons with symptoms from jobs that require food handling.
  • Pets with diarrhea should be examined by a veterinarian.
  • Water from a cistern connected to the eaves troughs is not a safe supply. Eaves troughs should not be connected to a cistern.
  • Avoid swallowing water during swimming from lakes, rivers and streams.

If you have cryptosporidiosis, do not swim in public water for at least two weeks after the diarrhea stops. Just being immersed in the water may contaminate it and spread the disease.

Recommended Absence

While symptoms are present, infected persons who work as food handlers or infected persons who provide care in hospitals, institutions where people live and child care centres should be excluded from work.

1. Ontario Ministry of Health and Ministry of Long Term Care Publications. Cryptosporidiosis. (2019).
2. Heymann. D.L. “Control of Communicable Diseases Manual”. 20th Edition. 2015. American Public Health Association: Washington D.C.
3. US Centers for Disease Control and Prevention website

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