In early October 2012, the Clark County Public Health Department (“the health department”) received the first reports of a cluster of Salmonella Virchow infections occurring in the county. Additional reports came in rapidly, and by October 9, interviews of ill persons indicated that the source of the developing outbreak was the On the Border restaurant in Vancouver, Washington.
On October 9, On the Border temporarily ceased operation. Dr. Alan Melnick, Clark County Health Officer, stated that the closure was “a further precaution to reduce the risk of Salmonella spreading to others.” Meanwhile, health department staff continued to interview employees and patrons of the restaurant to learn more about the precise cause of the outbreak. The health department also continued its work with On the Border employees to make sure that standard control measures—e.g. hand-washing and environmental sanitization—were in place and effective, so that when the restaurant resumed operation it would not pose a continuing threat to the health of its patrons. As of the date of the restaurant’s closure on October 9, there were 11 confirmed and five probable cases of Salmonella Virchow infection linked to the consumption of food at the restaurant.
The case count continued to rise, and by the end of the outbreak’s exposure period (September 20 through October 8, 2012), at least 120 people were suspected to have fallen ill. This case count included 43 laboratory-confirmed patients and another 77 who exhibited symptoms and had a corresponding exposure history at On the Border. The only Salmonella Virchow illnesses occurring in the country during this time frame arose from consumption of food at On the Border, including cases from Oregon and California who were traveling in the area when they were exposed, and sickened, at the restaurant. At least six people required hospitalization.
On the Border finally reopened for business on October 15, 2012. Environmental testing ultimately did not establish the precise cause of the outbreak—i.e. a specific food item or environmental exposure—but the overall epidemiological picture firmly established that, however it became contaminated, On the Border food was responsible for infecting all ill individuals.