E. Coli

What is E. coli and what is Shiga toxin?

E. coli are bacteria that normally live in the intestines of humans and animals. Although most strains are harmless, some can cause illness by making a toxin called Shiga toxin. The bacteria that make these toxins are called “Shiga toxin-producing” E. coli, or STEC for short.

Healthy cows, goats, deer and other animals can have STEC in their intestines and the bacteria can be present in their manure (droppings).

Who can get a STEC infection?

Anyone of any age can get a STEC infection, but the very young and the elderly are more likely to become seriously ill.

How is it spread?

People usually get STEC infection by eating contaminated foods or drinks that have not been thoroughly cooked or pasteurized (heat treated).

Cases and outbreaks of STEC infection have been traced to:

  • Eating undercooked or raw beef (especially ground beef) contaminated with manure during slaughter.
  • Drinking unpasteurized (raw) cow or goat milk contaminated with manure during milking.
  • Drinking unpasteurized juice or cider made with fruits that have fallen on the ground and been contaminated with animal manure.
  • Eating raw produce, including sprouts and leafy greens (such as spinach), contaminated with animal manure in the field or during processing.
  • Eating raw produce (or other ready-to-eat foods) contaminated by raw meat juices in the kitchen.

Infected people can spread STEC to others by not washing their hands thoroughly after having a bowel movement.

People can get STEC infection by having direct contact with livestock at fairs or petting zoos.

Swallowing water from STEC-contaminated lakes, streams and swimming pools can lead to infection.

What are the symptoms?

Some infected people have mild diarrhea or no symptoms at all.

Contact your healthcare provider if you have these symptoms:

  • Severe diarrhea
  • Stomach cramps
  • Blood in the stool

Usually little or no fever is present. People usually get sick from STEC between one and eight days (usually two to three days) after swallowing the bacteria.

How is STEC infection treated?

Most people with STEC infection get better on their own in five to ten days. Studies suggest antibiotics can make STEC infection worse. Treatment of STEC infection with antibiotics or anti-diarrhea medications is not recommended.

What serious complications can result from STEC infection?

A small number of people with STEC infection develop hemolytic uremic syndrome (HUS). This is a serious complication that can damage the kidneys and other organs. A prolonged hospital stay is often required. Fortunately, most people with HUS recover within a few weeks, but some suffer permanent kidney damage or die. Young children and the elderly are most at risk for this type of infection. Symptoms of HUS include decreased frequency of urination, feeling very tired and losing pink color in cheeks and inside the lower eyelids.

What can I do to prevent infection?

  • Do not eat raw beef or raw or under-cooked hamburger or other ground meat products. Cook all ground beef to 160 degrees F.
  • Keep ready-to-eat foods (i.e., raw vegetables) away from raw meat.
  • Drink only pasteurized (not raw) milk, milk products and fruit juices.
  • Carefully wash all produce, kitchen utensils and counter tops.
  • Wash your hands carefully with soap after using the toilet, changing a child's diaper, handling raw meat, or touching farm animals. Use hot, soapy water, rubbing your hands together for 20 seconds. Make sure your children wash their hands well after using the toilet.
  • If you have diarrhea, do not swim in pools or lakes and do not prepare food for others. Keep children in diapers out of pools and lakes.
  • Avoid swallowing water when swimming or playing in lakes, ponds, streams and pools.