Outbreak Statistics At a Glance
Source of Outbreak: Country Cottage Restaurant, Locust Grove, OK
Outbreak Organism: E. coli O111:NM
Vehicle of Contamination: Unknown
Method of Spread: Foodborne transmission
Confirmed Outbreak Period: Aug. 15-24, 2008
The Oklahoma State Department of Health (OSDH) released its final report today on the investigation of the largest E. coli O111 outbreak ever documented in the United States. The outbreak, which occurred in late August 2008 in northeastern Oklahoma, sickened 341 people and resulted in one death.
The report detailed the agency’s extensive epidemiological investigation into the outbreak that included laboratory testing, personal interviews, and an in-depth environmental investigation. While the source of the outbreak – the Country Cottage restaurant in Locust Grove, OK, – was quickly identified, the vehicle for contamination was never found.
Laboratory analyses of specimens provided by those who became sick allowed the OSDH and the federal Centers for Disease Control and Prevention (CDC) to pinpoint E. coli 0111 as the bacterial organism responsible for persons’ illnesses. However, microbiological testing of food products and food preparation and serving surfaces in the restaurant, as well as testing symptomatic restaurant employees, samples from a private water well located on the property, water filters, and the Locust Grove municipal water supply, found no E. coli 0111. The OSDH released multiple situational updates during the investigation that reported no E. coli 0111 had been identified in its extensive testing process. Because the disease-causing organism was not found, the OSDH was unable to eliminate from consideration any of the potential vehicles for transmission of the bacteria into the restaurant, including well water. Even so, analysis of data collected during the investigation suggests there was ongoing foodborne transmission of E. coli O111 to restaurant customers from Aug. 15-24, 2008.
“What is important to remember is that when responding to an infectious disease outbreak, our primary objective is to rapidly identify the source of the infection to contain the outbreak and prevent any further spread,” said State Epidemiologist Dr. Kristy Bradley. “Within 48 hours of being notified of increased cases of persons with bloody diarrhea being admitted to Tulsa area hospitals, we identified the Country Cottagerestaurant as the common source of transmission. The restaurant closed voluntarily and the outbreak was contained.”
According to the CDC, only 10 outbreaks involving E. coli 0111 had been reported nationally prior to Oklahoma’s outbreak. The bacteria are from the family of Shiga toxin-producing E. coli bacteria, or STEC. Persons who ingest STEC may have a diarrheal illness ranging from very mild and non-bloody to severe with very bloody stools. The infectious dose is very small and STEC are often spread by ingesting food items contaminated with fecal matter that are not subsequently cooked. Person-to-person transmission, direct animal contact, and waterborne transmission, either from contaminated drinking water or recreational water, are other exposure routes.
State health officials said as of March 16, 2009, OSDH personnel have reported 6,481 hours of total accrued time and effort dedicated to the E. coli O111 outbreak investigation. This does not take into account the time and effort provided by Tulsa Health Department personnel, student volunteers, or medical staff at various hospitals and clinics who provided surveillance information.