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Shiga toxin-producing E. coli (STEC) Overview and Prevention

What is STEC and what are the symptoms?

Escherichia coli (E. coli) are a group of bacteria. Most E. coli are harmless, but some, like Shiga toxin-producing E. coli (STEC), cause illness. Most people infected with STEC develop diarrhea (often bloody), stomach cramps, and vomiting. Symptoms typically start within 3 to 4 days after being exposed, but it can take longer. Sometimes people infected with STEC have no symptoms at all, but they can still pass the bacteria to others.

How long does it last?

Most people infected with STEC typically feel better in 5 to 10 days and usually recover with fluids and rest. It is recommended to avoid antibiotics and antidiarrheal medicines, such as Imodium®, because they can prolong or worsen symptoms. Some people with severe symptoms may need to be hospitalized and others may develop a severe complication called hemolytic uremic syndrome (HUS).

How does it spread?

STEC bacteria live in the intestines of people and animals. Transmission occurs in the following ways:


Eating foods that are contaminated with feces from an infected animal, from environmental contamination, from cross-contamination in a kitchen, or eating foods that were prepared by someone who is sick with STEC.


Swallowing water while swimming or drinking water contaminated with STEC bacteria.

Person-to-Person Contact

Some infections occur when the bacteria passes from the stool or soiled fingers of one person to the mouth of another person either through food handling or direct contact.

Animal Contact

Touching or handling animals or their environments.

How can I prevent STEC infections?

Wash your hands with soap and water before preparing or eating foods, having contact with animals or their environment, and after using the bathroom or changing a diaper.

Practice food safety: Avoid cross-contamination in the kitchen, wash and cook foods thoroughly, store foods properly, and avoid unpasteurized (raw) dairy products and juices.

If you have diarrhea, do not handle, prepare, or cook foods for others at home or at your job until your symptoms have resolved.

Cases shall not work as food handlers or in sensitive occupations until diarrhea has ceased for at least 24 hours and two consecutive negative stool specimens are obtained.

Avoid swallowing water from ponds, lakes, and untreated swimming pools, and, if you have diarrhea, avoid swimming until your symptoms have resolved.