Wisconsin E. Coli Outbreak Matter of Washing Hands

August 24, 2001

The Ozaukee County (Wisconsin) Public Health Department said people who became ill from an E. coli O157:H7 outbreak associated with the Ozaukee County Fair failed to wash their hands after coming into contact with animals in barns or at a petting zoo. "Careful analysis of the information collected from individuals who fell ill after the Fair indicates that the cause of infection was individuals visiting the animal barns or petting zoo or touching animals and then not washing their hands before eating," said Ozaukee County Public Health Director Glenda Madlom.

"We examined all possible sources of E. coli O157:H7 through careful analysis of the interviews of fair attendees and testing of numerous water, manure and environmental samples," said Herb Bostrom, director of the Bureau of Communicable Diseases. "The source was clear from the resulting data."

The statistical analysis of epidemiological data indicated no association with food or beverages provided by any vendor at the fair; fishing in or any other contact with the pond; exhibiting an animal at the fair; routine risk factors outside the fairgrounds (e.g. drinking unpasteurized milk or juices, having a child in day care, swimming in lakes or streams, or eating raw or undercooked ground beef).

Of the 55 human stool specimens received, 13 have been confirmed positive for E. coli O157:H7 and 42 are pending. In addition to analysis of interview questionnaires, multiple environmental samples have been tested. These include 56 water samples and six composite manure samples. All of these environmental samples have tested negative for E. coli O157:H7 with one sample result pending.

"We will be issuing a final written report regarding the investigation within the next couple of months," said Bostrom. "This report will include the methods used in the investigation, the results of the investigation, and recommendation to reduce the possibility of a similar occurrence in the future."