In early November 2017 Wisconsin local and state health authorities were notified of two unrelated salmonellosis cases. When interviewed, both cases reported attending a “Murder Mystery” event at Le Chateau on October 26th, 2017 and October 28th, 2017. Le Chateau is a French restaurant that serves a complex menu, serving only 35 meals a day on average. Both cases also reported having meal companions who fell ill after the event.
On November 16, 2017 La Crosse County Health Department initiated a foodborne outbreak investigation. Contact information for all parties and groups was gathered from Le Chateau, and a list of all foods served at this event over the course of the three days was generated. A total of roughly 150 people attended the “Murder Mystery” event over the course of the three days. 57 of those attendees were interviewed by Wisconsin Department of Health Services. Of those, 18 people reported becoming ill with symptoms consistent with Salmonella infection between 1 to 5 days after dining at Le Chateau. Stool samples were tested from five of these patients in total. These five stool samples all cultured positive for the same strain of Salmonella–S. enteritidis, indicating that all five patients were likely exposed to the same source of infection.
Of the 57 attendees interviewed, 29 people were considered as control in a case-control study conducted by La Crosse County Health Department and Wisconsin Department of Health. The rest of the 57 people were excluded from the study due to inadequate information. The epidemiologic case-control analysis concluded that the consumption of chicken kabobs at Le Chateau between October 26th, 2017 and October 28th, 2017 was significantly associated with illness. More so, multiple attendees reported to the public health officials that the chicken kabobs appeared undercooked during the event. No other foods were found to be significantly associated with illness. Although La Crosse County Health Department was unable to collect any food sample from this event to test for Salmonella enteritidis due to the delay in reporting and investigation, results from interviews, the case-control study, and the environmental assessment of Le Chateau indicate that food served at the “Murder Mystery” events was the most likely cause of infection in the attendees.