Public Health – Dayton & Montgomery County announced today that following an intensive investigation into the July outbreak of O157 in Germantown, they were unable to determine the cause of the outbreak.
The outbreak resulted in 79 cases of E. coli O157 foodborne illness being reported. Two of those were secondary cases resulting from contacts of primary cases. Twenty persons tested positive by laboratory analysis, 14 were hospitalized, 3 developed hemolytic uremic syndrome, and unfortunately one death occurred.
The outbreak investigation involved:
• Where the foods at the event originated
• How food was stored, handled, and maintained prior to and during the event
• In-depth interviews with 117 individuals who attended the event
• An epidemiological analysis of the data obtained through the interviews
• An environmental assessment of the sites where the event was held and where the hogs that were roasted were produced and slaughtered
• Consultation and involvement with the Ohio Department of Health, the Ohio Department of Agriculture, and the United States Department of Agriculture
Public Health was unable to determine the cause of the outbreak.
Items of note:
Because the investigation of the outbreak began on July 9, when the first reports of illness occurred, there were no food items left for examination, since the picnic occurred on July 3.
The food at the event was provided by the host and by the 300+ individuals who brought carry-in foods.
In addition, it was not possible to know with certainty the actual conditions and temperatures of food preparation and handling at the event or in the homes of those who brought carry-in items.
The statistical analysis of data from the 117 interviews did not conclusively link any of the meat items to having caused the illness.
Background information on investigation:
E.coli O157 Outbreak
A picnic was held at Neff’s Lawn Care in Germantown, Ohio on July 3, 2012. As a result of eating food at this picnic, 79 cases of E. coli O157 foodborne illness were reported. Two of those were secondary cases, (contacts of primary cases). Twenty persons tested positive by laboratory analysis, 14 were hospitalized, 3 developed hemolytic uremic syndrome, and unfortunately one death occurred.
It was estimated that over 300 attended the picnic and ate food. Additionally, approximately 2000 were in attendance for a fireworks celebration on the grounds after the picnic. No one who attended only the fireworks show became ill. The primary attack rate among those who ate at the picnic is estimated at 26.3 % (79/300).
Food for the event was provided by the sponsors and the attendees. Two hogs were roasted off-site and delivered to the event at meal time. Hamburgers and hot dogs were grilled at the site and served. Over 100 carry-in side dishes were brought by attendees and placed out for service.
Public Health – Dayton & Montgomery County (PHDMC) became aware of the outbreak on July 9, 2012, when it was reported that 5 individuals presented to a local hospital with similar symptoms of diarrhea and rectal bleeding. Initial interviews of those persons indicated they all attended and ate food at the picnic.
PHDMC’s investigation included interviewing the hosts and inspecting the facility where the event was held. Interviews and inspections were also conducted with the supplier of the hogs and the cooker of the hogs served at the picnic. Additional cases were identified by outreach to the public through the media and monitoring hospital admissions, consulting with local doctors and laboratories. Consultations with the Ohio Department of Health, Ohio Department of Agriculture, and the U.S. Department of Agriculture were made throughout the investigation.
Water samples of the wells at the picnic site and the site where the hogs were roasted were taken and tested negative for E. coli or other pathogens. Environmental samples were taken at the farm where the hogs were produced and slaughtered and tested negative for E. coli. There were no leftover foods from the picnic available for laboratory testing.
Interviews were conducted of sixty-five ill persons to determine symptoms, onset and duration of illness, and food histories. Persons who did not become ill that attended the picnic were also interviewed to determine food histories. A case-control study comparing ill individuals (cases) to those who attended the picnic but did not become ill (controls) was conducted to determine which meat item may have been the source of the E. coli outbreak. Since numerous side dishes were carried into the event, a low number of attendees ate the same side dish, and there was no inventory of the carried-in foods. Therefore, it was only possible to analyze the data involving the meats offered at the picnic. Sixty-five cases and 52 controls were interviewed to determine if they consumed plain pork, barbeque pork, hamburgers, and/or hotdogs at the picnic. Statistical analysis from the case-control study did not conclusively link any of the meat items to having caused illness.
PHDMC could not verify cooking, cooling, holding or reheating temperatures or food handling practices for any of the food products as they came from multiple sources and this picnic was not a regulated (licensable) event.
It is inconclusive as to what food item or other environmental factor caused this outbreak of E. coli O157.
This outbreak illustrates the importance of proper food handling as CDC estimates that about 48 million people (1 in 6 Americans) get sick, 128,000 are hospitalized, and 3,000 die each year from foodborne diseases.