by Scholten A


Cryptosporidiosis is an infection in the intestines. It is a minor problem for most people. But, it can be life-threatening for young children, the elderly, and those with weak immune systems.

The Intestines
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A certain parasite causes cryptosporidiosis. It often enters the body through food or drink that has the parasite. It can also be passed from contaminated water, soil, or stool (poop). Common ways are:

  • Water from lakes, streams, hot tubs, swimming pools, or water parks
  • Ice cubes
  • A baby's dirty diapers
  • Touching animals, cleaning cages, or going to barns or petting zoos
  • Eating food grown in soil
  • Eating or drinking unpasteurized dairy products or apple cider

Risk Factors

The infection is more common in children 2 years of age or less. Other things that raise the risk are:

  • Being or working in day care or a group setting
  • Conditions that weaken the immune system such as cancer, HIV , or an organ transplant
  • Swimming in or drinking contaminated water
  • People who have oral to anal contact during sex


Most people do not have symptoms. If symptoms happen, they may cause:

  • Watery stools (poop)
  • Belly cramps
  • Nausea or vomiting
  • Slight fever
  • Weakness
  • Loss of hunger
  • Weight loss

These symptoms can lead to dehydration.


The doctor will ask about symptoms and past health. A physical exam and stool tests may be done.


In most people, the infection goes away on its own.

Treatment may be needed for those with severe and longer lasting infection. It may involve:

  • IV fluids
  • Medicine to control diarrhea
  • Antiparasitic medicine


To reduce the risk of cryptosporidiosis:

Wash hands often, mainly:

  • After using the toilet and changing a diaper.
  • Before handling or eating food.
  • After being with animals, people who are sick, or being in soil.

In general:

  • Use safe water. Also, wash fruits and vegetables in safe water.
  • Try not to swallow while playing or swimming water.
  • Do not eat or drink unpasteurized dairy products or apple cider.
  • Use barriers when having oral sex.


Centers for Disease Control and Prevention 

IDSA—Infectious Diseases Society of America 


Canadian Public Health Association 

Health Canada 


Cryptosporidiosis. EBSCO DynaMed website. Available at: Accessed August 25, 2021.

Cryptosporidiosis. New York Department of Health website. Available at: Accessed August 25, 2021.

Desai AN. Cryptosporidiosis. JAMA. 2020;323(3):288.

Foodborne illnesses. EBSCO DynaMed website. Available at: Accessed August 25, 2021.

Parasites—cryptosporidium (also known as crypto). Centers for Disease Control and Prevention website. Available at: Accessed August 25, 2021.

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