BACKGROUND: On November 14, 2016, the Alabama Department of Public Health (ADPH), Infectious Disease & Outbreaks Division (ID&O) investigated a gastrointestinal illness outbreak following a wedding. The wedding reception was attended by 150 individuals. The food for the reception was prepared across jurisdictional lines in a separate county, and health area, than where the reception took place.
METHODS: The investigation consisted of a surveillance line list to capture information on the individuals who reported eating at the wedding reception and their demographics. The menu from the wedding was used to create an Outbreak-Specific Questionnaire (OSQ) in Epi Info 7™ and disseminated via email. Stool specimens were requested from the ill to identify the etiologic agent(s) and submitted for laboratory testing by the State Laboratory, where pulsed-field gel electrophoresis (PFGE) was performed on isolates. Environmental Science was sent to the wedding venue and catering facility on November 14 to conduct an inspection and collect environmental specimens. A case was defined as an individual who ate food from the wedding on November 12, 2016, and became ill with diarrhea or vomiting within three days. A case was further defined as confirmed or probable. A confirmed case met the above criteria and had cultured laboratory confirmation of the identified organism Salmonella enteritidis. A probable case was defined as anyone who met the above criteria without cultured laboratory confirmation.
RESULTS: Seventy-one OSQs were analyzed. According to the OSQs, the risk of illness was 3.88 times higher for those who consumed grilled chicken than those who did not (p<0.01). Individuals who consumed the parmesan mashed potatoes where 1.94 times more likely to become ill than those who did not (p<0.01). Sixty-four individuals were identified as part of this outbreak, meeting Confirmed or Probable case definitions. The BCL determined that 28 isolates from clinical specimens associated with this wedding outbreak had the Salmonella enteritidisPFGE pattern JEGX01.0021, which matched the PFGE patterns from 3 food samples associated with this outbreak. The OSQ showed a commonality of consumption of grilled chicken and mashed potatoes.
CONCLUSIONS: Using Epi Info web-based survey for the OSQs allowed ID&O to quickly distribute and analyze surveys, which led to targeted testing and identification of contaminated food items. Epidemiologic and laboratory data suggest that the route of transmission was the result of cross contamination which highlights the importance of proper food preparation practices among food service providers.