On September 30, 2017, the Chincoteague Volunteer Fire Company (CVFC) hosted its 18thAnnual Chili/Chowder Cook-off and Classic Car Show at the carnival grounds in Chincoteague, Virginia. The fire company estimated 2,500 people from multiple states in the region attended the event.

After the event, some attendees developed gastrointestinal (GI) illness. The first complaint of suspected foodborne illness was received by the Accomack County Health Department (ACHD) on October 3. On the same day, ACHD found dozens of reports of GI illness in a conversation (started on October 2) on a social media page for Chincoteague Island residents and visitors. Some of the ill cook-off attendees reported seeking health care and receiving diagnoses of Salmonella infection.

Background: After a chili and chowder cook-off featuring 12 local vendors and attended by ~2,500 people, the Accomack County Health Department received reports of gastrointestinal illness among event attendees. Clinical stool specimens tested positive for Salmonellaserotype Javiana. An investigation was conducted to determine the source of—or practices that might have contributed to—contamination, and provide recommendations to prevent future outbreaks at similar events.

Methods: A cohort study was performed, with event attendees recruited through press releases and subsequent social media posts containing the link to an online survey asking about foods consumed at the cook-off and gastrointestinal illness. A case was defined as three or more episodes of diarrhea in less than 24 hours, or unquantified diarrhea in addition to at least one other symptom (abdominal pain, chills, dehydration, fever, nausea, or vomiting) in someone who consumed cook-off food. In addition to unadjusted relative risks (RRs), Mantel-Haenszel adjusted RRs were calculated to address potential confounding by multiple exposures. Environmental health specialists interviewed food handlers and conducted inspections of restaurants where professional competitors prepared food. Available food samples and stool specimens from ill attendees and asymptomatic food handlers were tested for Salmonella. Primary Salmonellaisolates were subtyped by pulsed-field gel electrophoresis (PFGE) and further characterized by whole-genome sequencing (WGS).

Results: Of 438 survey responses, 171 met the case definition. Of all exposures, Chowder A, prepared for the event by a professional vendor off-site, had the strongest association with illness (RR: 8.9; 95% confidence interval: 5.7–13.7). When stratified by exposure to Chowder A, all other chili or chowder adjusted RRs were less than 1.4. Environmental health inspections and interviews did not identify a specific source of contamination.Salmonella serotype Javiana was identified in stool specimens from 25 ill local and out-of-state attendees and an uneaten sample of Chowder A, but was not identified in the food handler specimens or raw frozen clam strips.

Conclusions: Epidemiologic and laboratory analyses provide evidence Chowder A was the most likely source of illness; however, the original source of Salmonellacould not be identified. Recommendations to prevent future outbreaks included requiring all food to be prepared at the event site and ensuring safe temperatures are maintained during food preparation and service.

Chincoteague Chili Cookoff- VA DOH General Outbreak Report