What is Escherichia coli 0157:H7?

E. coli O157:H7 is one of hundreds of strains of the bacterium Escherichia coli. Although most strains are harmless and live in the intestines of healthy humans and animals, this strain produces a powerful toxin and can cause severe illness.

What are the symptoms of E. coli 0157:H7?

E. coli O157:H7 infection often causes severe bloody diarrhea and abdominal cramps but sometimes the infection causes non-bloody diarrhea or no symptoms. Usually little or no fever is present, and the illness resolves in 5 to 10 days.

In some persons, particularly children under 5 years of age and the elderly, the infection can also cause complications that lead to kidney failure; however, only about 2 to 7 percent of infections lead to this complication.

How is E. coli 0157:H7 spread?

E. coli O157:H7 infections can typically be traced back to cattle. Meat can become contaminated during slaughter, and organisms can be thoroughly mixed into beef when it is ground. Bacteria present on the cow's udders or on equipment may get into raw milk.

Eating meat, especially ground beef that has not been cooked sufficiently to kill E. coli O157:H7 can cause infection. Contaminated meat looks and smells normal. Although the number of organisms required to cause disease is not known, it is suspected to be very small.

Among other known sources of infection are consumption of sprouts, lettuce, salami, unpasteurized milk and juice, and swimming in or drinking sewage-contaminated water.

E. coli 0157:H7 can be passed from person-to-person if a person has the infection—even if they don’t have any symptoms—and proper hand washing procedures are not followed. This is particularly a problem for children in diapers.

How can I keep from getting E. coli 0157:H7?

Ways to prevent infection with E. coli O157:H7 include:

Cook all ground beef and hamburger patties thoroughly. Ground beef should be cooked until a thermometer inserted into several parts of the patty, including the thickest part, reads at least 160º F.

In your kitchen, keep raw meat separate from ready-to-eat foods. Wash hands, counters, and utensils with hot soapy water after they touch raw meat. Never place cooked hamburgers or ground beef on the unwashed plate that held raw patties. Wash meat thermometers in between tests of patties that require further cooking.

Drink only pasteurized milk, juice or cider.

Wash fruits and vegetables thoroughly, especially those that will not be cooked.

Avoid swallowing lake or pool water while swimming.

If someone has diarrhea, especially a child, make sure he/she  washes his/her hands carefully with soap after bowel movements to reduce the risk of spreading infection. Hands should also be washed carefully after changing soiled diapers.

Anyone with a diarrheal illness should avoid swimming in public pools or lakes, sharing baths with others, and preparing food for others.

If I’ve been exposed to E. coli 0157:H7, how long will it take for symptoms to develop?

Symptoms usually occur within 2-3 days following exposure, but may occur as soon as 1 day following exposure or up to one week following exposure.

What treatments are available for E. coli 0157:H7? How serious is the disease?

Most persons with E. coli O157:H7 recover without antibiotics or other specific treatment in 5-10 days. There is no evidence that antibiotics improve the course of disease, and it is thought that treatment with some antibiotics may precipitate kidney complications. Antidiarrheal agents, such as Imodium, should also be avoided.

Generally, if people are hospitalized, it is due to dehydration, electrolyte depletion or for kidney complications.

What does the Health Department doing to prevent the spread of E. coli 0157:H7?

The Health Department’s Epidemiology Services staff investigates all cases of E. coli 0157:H7 to determine the source of the illness. Physicians’ offices and laboratories are required to report all cases of E. coli to the Health Department.

The Health Department’s Environmental Health and Safety staff works with local food operators and food service establishments to ensure that the food safety standards are met.

Where can I get more information on E. coli 0157:H7?

For more information online, you can visit the Centers for Disease Control at http://www.cdc.gov/ecoli/, or the Food and Drug Administration at http://www.fda.org.

Or, for more information on the Health Department’s programs, please call 859.341.4264.