July 11, 1996
E. COLI 0157:H7 CLUSTER LINKED TO EATING RED LEAF LETTUCE
SPRINGFIELD, IL -- The Illinois Department of Public Health today announced that consumption of red leaf lettuce has been linked to a cluster of severe diarrhea and abdominal cramps in six Illinois counties.
A joint investigation by the Department, local health departments and the U.S. Centers for Disease Control and Prevention (CDC) has implicated red leaf lettuce served at restaurants and purchased for home consumption at a variety of food stores, Dr. John R. Lumpkin, state public health director, said.
Twenty-seven of 66 persons who have become ill in Illinois since the end of May from E. coli 0157:H7 bacteria, which is present in human and cow waste, have been determined to be of the same type through DNA fingerprinting performed by the CDC. By identifying the specific genetic makeup of the bacteria, investigators are able to tell the illness comes from the same source. Food histories of those who are ill were then compared and red leaf lettuce was the only food item implicated.
Other cases may be attributed to red leaf lettuce as additional laboratory tests are completed. Of the 27 people who became ill between May 28 and June 14, 18 are from Cook County, including five from the city of Chicago; two in DuPage County; one in Kane County; one in Lake County; one in Peoria County; and four in Winnebago County.
The supply of red leaf lettuce implicated in the outbreak is believed to be no longer available in Illinois stores. Tracing the lettuce to where it was produced is underway.
"This cluster of cases reinforces the importance of thoroughly rinsing all fresh fruits and vegetables with tap water if they are to be served uncooked. Leaf lettuce, in particular, should be washed one leaf at a time," Dr. Lumpkin said. "In recent years, outbreaks of gastrointestinal illness, including E. coli 0157:H7, have been linked to the consumption of food items, such as lettuce, tomatoes, alfalfa sprouts, cantaloupe, strawberries and raspberries."
Although it is not known how the red leaf lettuce became contaminated with E. coli 0157:H7, investigators say the product could have come in contact with the bacteria in the field if animal waste was used as fertilizer or if the product came in contact with sewage contaminated water, or during shipping and handling.
E. coli 0157:H7 causes severe, often bloody, diarrhea and painful abdominal cramps. In some persons, particularly children younger than 5 years of age and the elderly, the infection can lead to hemolytic uremic syndrome (HUS), which can result in stroke, seizures and death.
Of those reported ill with E. coli 0157:H7, about half have required hospitalization, but no deaths have been attributed to the bacteria.
CDC has completed genetic testing on 52 cases; the 25 cases not associated with consumption of red leaf lettuce are of numerous different types of E. coli 0157:H7 and not believed to be linked.
Besides fruits and vegetables, E. coli 0157:H7 cases can come from undercooked ground beef. Beef that is still pink, or has blood-tinged juices, has not been cooked enough to kill the bacteria. The organism can be found in the intestines of cattle and, when the animals are slaughtered, the meat can be contaminated by intestinal contents. When the meat is ground, fecal organisms on the outside of the meat are then thoroughly mixed throughout the ground beef. These bacteria can survive unless the meat is thoroughly cooked. Work surfaces that come in contact with raw ground beef also should be thoroughly cleaned before using again.
The bacteria is present in the stools of infected persons and can be passed from one person to another if hygiene and hand washing habits are inadequate.
of Public Health
535 West Jefferson Street
Springfield, Illinois 62761
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