Foodborne Illness

A resource for foodborne illness.


Cryptosporidium parvum, also known as “Crypto,” is a parasite found in food and water that has been contaminated by feces from humans or animals. It is highly resistant to normal levels of chlorine, and can survive in pools and drinking water. People usually get cryptosporidium from swallowing contaminated water, eating contaminated food, or coming into contact with contaminated feces. Ingestion of as few as two to ten cryptosporidium oocysts, or parasites, can cause infection.

Over 10 cryptosporidium outbreaks from contaminated water have been documented in the United States since 1988, infecting thousands of people.

Symptoms of Cryptosporidium Infection

Symptoms of cryptosporidium infection, or cryptosporidiosis, generally appear a week after the parasite is swallowed. Signs that one is infected by a cryptosporidium parasite include the following:

  • Diarrhea - diarrhea will be profuse and watery

Abdominal crampingFatigueFeverNauseaLoss of appetite

High-Risk Population

Those at increased risk of infection with cryptosporidium include people with weak immune systems, the elderly, small children, and pregnant women.

Diagnosis of Cryptosporidium

The most common way to diagnose cryptosporidiosis is by analyzing a stool sample. If you think you have symptoms of crypto infection, consult your doctor to get a stool sample tested.

Treatment for Cryptosporidiosis

There is no specific treatment for cryptosporidiosis, but most healthy people recover within two weeks. Symptoms can be lessened with an anti-parasitic drug and anti-diarrhetic agents. In addition, one should replenish the fluids and electrolytes lost during diarrhea.

Prevention of Cryptosporidium

Avoiding cryptosporidium is especially important for people with weak immune systems, as the illness caused by cryptosporidiosis can have worse effects on these individuals. In order to prevent the spread of cryptosporidium, one should:

  • Wash hands thoroughly after going to the bathroom, changing diapers, and before and after eating

Wash all raw foods and vegetables before eating themBe careful of swimming in public areas such as lakes and swimming pools if contamination is suspected, as cryptosporidium can linger up to six months in waterWash hands after touching farm animalsAvoid exposure to feces during sexual activity

Outside References

Mayo Clinic. (2010). Cryptosporidium infection. Available at

Clostridium Perfringens

Connect with Marler Clark


1012 First Avenue
Fifth Floor
Seattle, WA 98104


M-F, 8:30 am - 5:00 pm, Pacific

Call toll free:

1 (800) 884-9840

If you have questions about foodborne illness, your rights or the legal process, we’d be happy to answer them for you.