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Nov
04

Shiga toxin-producing E. Coli (STEC)

General information about Shiga toxin-producing E. coli (STEC) including symptoms and how to avoid spread.

E. coli germs (bacteria) normally live in the intestines of humans and animals. Many strains of E. coli bacteria exist, and most of them are harmless or beneficial to human health. STEC are strains of E. coli that produce Shiga toxin (such as E. coli O157:H7) and can cause serious illness in people.

Causes

Infection with STEC can occur through consumption of:

  • Undercooked ground beef and other beef products
  • Unpasteurized (raw) milk, cheese, or juice
  • Contaminated raw fruits, vegetables, sprouts, and herbs
  • Water contaminated with animal feces
  • Direct contact with farm animals or their environment
  • Ready-to-eat foods can also be contaminated with STEC through contact with raw beef or raw beef juices in the kitchen.

STEC and other foodborne infections occur throughout the year but may increase during late spring and summer months.

Symptoms and their duration

Symptoms of STEC include diarrhea (which often becomes bloody) and stomach cramps, with mild or no fever. Illness typically lasts several days and people can spread infection to others even after symptoms resolve.

STEC infections usually resolve in 5 to 7 days but recovered individuals may still spread the bacteria. Up to one third of children may continue to shed STEC for as long as 3 weeks.

Around 5 to 10% of those who are diagnosed with STEC infection develop a potentially life-threatening complication known as hemolytic uremic syndrome (HUS). Clues that a person is developing HUS include decreased frequency of urination and feeling very tired.

People with HUS should be hospitalized because their kidneys may stop working and they may develop other serious problems. Most people with HUS recover within a few weeks, but some suffer permanent damage or die.

What to do when sick

  • Ill people with suspected STEC infection should not work in food handling, patient care, or childcare settings.
  • Sick children with suspected STEC infection should not attend childcare until they have seen a healthcare provider and been tested for STEC infection, even if their illness is mild.
  • People with STEC infections who work in or attend these sensitive settings must be cleared by Public Health – Seattle & King County before returning.

Reduce your risk

  • Avoid eating high-risk foods, especially undercooked ground beef and other beef products, goat products, and sheep products. Also avoid unpasteurized (raw) milk, juice, or cheese, and raw sprouts.
  • Wash hands with soap and water before preparing food for yourself or your children, before eating food, after handling raw meats, after going to the bathroom or changing diapers, and after contact with cows, sheep, or goats, their food or treats, or their living environment.
    • If soap and water aren't available, use an alcohol-based hand sanitizer with at least 60% alcohol (check the product label to be sure). These alcohol-based products can quickly reduce the number of germs on hands in some situations, but they are not a substitute for washing with soap and running water.
  • Thoroughly wash fresh produce before eating.
  • If washing "pre-washed" or "ready to eat" produce items, be sure it does not come into contact with unclean surfaces or utensils.
  • Wash cutting boards and counters used for meat or poultry preparation immediately after use to avoid cross contaminating other foods.
  • Cook all meats thoroughly, especially ground beef. Use a food thermometer to make sure meats have reached a safe internal temperature.
    • Cook ground beef and pork to a minimum internal temperature of 160°F.
    • Cook beef steaks, beef roasts, goat, and lamb to an internal temperature of at least 145°F and allow to rest for 3 minutes after you remove meat from the grill or stove.

Resources for health care professionals

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