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Escherichia coli O157:H7

A bacterial disease
What is it?
Photo of E. ColiPhoto credit: Elizabeth H. White, M.S.

Escherichia coli, a type of bacteria, is a leading cause of food-borne illnesses. It lives in the intestines of healthy animals. There are hundreds of strains of E. coli, most of them harmless. But E. coli O157:H7 produces a powerful toxin that can cause severe bloody diarrhea and occasionally kidney failure.

How do I avoid it?

  • Cook all beef thoroughly
  • Keep raw meat separate from other foods, and never place cooked burgers on the unwashed plate that held raw patties. Wash hands, counters and utensils with hot, soapy water after touching raw meat.
  • Drink only pasteurized milk, juice or cider.
  • Wash fruits and vegetables under running water.
  • Drink clean water only. Avoid swallowing lake or pool water while swimming.
  • Wash hands thoroughly with soap and water after using the toilet or changing diapers.

What are the symptoms?

People typically become ill from E. coli O157:H7 two to eight days after exposure to the bacteria. Symptoms include:

  • bloody diarrhea
  • abdominal cramps
  • little or no fever
Some people may contract the bug but show no symptoms. Usually the illness runs its course in five to ten days. But in some cases the infection can cause a complication called hemolytic uremic syndrome (HUS), which destroys red blood cells and causes kidney failure.

How do I get it?

The organism can be found on most cattle farms and many petting zoos. Humans can become infected by:

  • Eating meat, especially ground beef that has not been cooked sufficiently
  • Eating unwashed sprouts, lettuce or spinach, drinking unpasteurized milk or juice, and swallowing contaminated water
  • Person-to-person contact with infected individuals, especially within families or child care centers
  • Contact with animals or other contaminated items in petting zoos

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