Cryptosporidium parasite
Cryptosporidium parasite

Cryptosporidium is a microscopic parasite that causes watery diarrhea. The parasite and the disease are commonly called "Crypto." This disease can infect both animals and humans. Crypto can be found in soil, water, food, or on surfaces.


On this page

  • Spread of Cryptosporidiosis
  • Signs and Symptoms of Cryptosporidiosis
  • Diagnosis and Treatment for Cryptosporidiosis
  • Prevention of Cryptosporidiosis
  • Resources for the Public


    Spread of Cryptosporidiosiscalf laying down

    Crypto lives in the gut of infected animals. An infected animal passes the parasite in their stool. People get Crypto when they swallow the parasite. Crypto can be spread by:

    • Swallowing contaminated water from pools, fountains, lakes, or rivers
    • Contact with sick animals
    • Drinking untreated water
    • Swallowing contaminated water, ice, or beverages
    • Eating undercooked food or drinking unpasteurized milk or cider
    • Drinking contaminated raw milk or apple cider

    Crypto is not spread through contact with blood.


    Signs and Symptoms of Cryptosporidiosis

    Symptoms of Crypto usually start two to ten days (average of seven days) after swallowing the parasite. Symptoms usually last one to two weeks, but can range from a few days to four or more weeks. See a healthcare provider if you have symptoms of Crypto. Symptoms include:

    • Watery diarrhea (this is the most common symptom)
    • Stomach pain
    • Dehydration
    • Nausea and vomiting
    • Fever
    • Weight loss

    Some infected people do not have any symptoms. People with weak immune systems may develop serious, chronic, and sometimes fatal illness.


    Diagnosis and Treatment for Cryptosporidiosis

    Crypto is diagnosed by testing stool for the parasite.

    Most people with healthy immune systems do not need treatment and will recover on their own. It is important to drink plenty of fluids to prevent dehydration.


    Prevention of Cryptosporidiosisperson washing their hands

    The following steps can lower your chance of getting and spreading Crypto:

    • Always wash your hands after using the toilet, changing diapers, and before handling food.
    • Always wash your hands after touching cows and other animals.
    • Do not swim in lakes and pools when you have diarrhea.
    • Do not drink raw milk and other unpasteurized dairy products or apple cider.
    • Do not drink from streams, brooks, or lakes when hiking or camping.
    • When traveling in developing countries, do not drink water unless it is boiled and avoid ice cubes.


    Resources for the Public