According to news reports, as of Friday afternoon, Clark County health officials have confirmed 21 cases of Salmonella Virchow and report 55 probable cases. The cases involve mostly adult customers who visited the On the Border restaurant between Sept. 20 and Oct. 8. Five restaurant food handlers and at least one child also tested positive. The exposure dates stretch into October. Health officials closed the restaurant Tuesday.

Health officials are still working to determine the source of the bacteria, but they may never be able to pinpoint exactly what caused people to get ill. Health inspectors have collected samples from environmental surfaces and food handlers. Restaurant employees have thrown away all opened food and ice and are working to clean and sterilize the entire restaurant.

The restaurant will not be allowed to reopen until health officials are confident the public is no longer at risk.