Official websites use

A website belongs to an official government organization in the City of Boston.


Secure .gov websites use HTTPS

A lock or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Last updated:

Shiga toxin-producing E. coli (STEC)

This fact sheet answers frequently asked questions about Shiga toxin-producing E. coli (STEC).

Shiga toxin-producing E. coli (STEC) is one of hundreds of strains of E. coli bacteria that live in the bowel of people and animals. Most strains of this germ are harmless, but the STEC strain produces a powerful toxin and can cause severe illness.

The basics

How is STEC diagnosed?

Diagnosing infection with this germ requires stool sample testing. It is not a routine test, so if your health care provider thinks you may have STEC, they must ask the lab to test for it. Anyone with bloody stool (that is not known to be due to another cause) should get tested for STEC.

Are there any restrictions for people with STEC?

Yes because STEC is a disease that spreads to other people, health care providers must report cases of STEC to the local board of health. To protect the public, workers at food-related businesses who have STEC must stay out of work until they don’t have diarrhea and two lab tests on a stool sample show no STEC germs.

Workers in food-related businesses who have diarrhea and live with someone who has STEC must also show that they have none of the germs in their stool. Food-related businesses include restaurants, sandwich shops, hospital kitchens, supermarkets, dairy, or food-processing plants. This regulation also includes:

  • workers in schools
  • residential programs
  • day-care and health care facilities that feed, give mouth care, or dispense medications to clients


What are the symptoms?

The most common symptoms are severe bloody diarrhea and stomach cramps. Some people vomit or have a fever, but these are less common. Symptoms usually go away by themselves after 5 to 10 days. In a small number of people, this strain of E. coli can cause a rare but serious problem called hemolytic uremic syndrome (HUS).

What is HUS?

HUS is a disease that destroys red blood cells and cause kidney failure. This complication occurs primarily in children under the age of 5 and in the elderly. Most people who get HUS recover with no remaining blood or kidney problems.

How is it spread?

STEC lives in the intestines of a small number of goats, sheep and ruminant animals. STEC can contaminate the meat of slaughtered animals. Bacteria can also be present in cows’ udders and get into raw milk. It spreads to people who eat or drink these contaminated undercooked and unpasteurized animal products.

Bacteria from the stool (feces) of an infected person can spread to others if the person does not wash their hands thoroughly with soap and water. This can occur during food preparation, but most often happens in families and day care centers. A person can still spread the illness to others for up to two weeks after they stop having symptoms.


How can I prevent the infection?

The most important things to remember are that the germs can only make you sick if you swallow them. Thoroughly washing your hands with soap and water, and thoroughly cooking food kills the germ.

Follow the prevention tips below:

  • Thoroughly cook all ground beef. Do not eat any ground beef that is still pink in the middle
  • If you receive undercooked ground beef in a restaurant, send it back for further cooking. Ask for a new bun and a clean plate as well
  • Do not put cooked meat or other prepared food on an unwashed dish or cutting board that touched raw meat
  • Do not eat unpasteurized dairy products (such as cheese or milk), juice, or cider
  • Wash fruits and vegetables thoroughly, especially if you eat them raw
  • Avoid swallowing lake or pool water when swimming
  • Wash your hands thoroughly with soap and water after using the bathroom


How is the illness treated?

Most people recover without antibiotic treatment. Avoid using antibiotics and antidiarrheal medicine.

Back to top