In a medical mystery involving one of Detroit’s largest hospitals, more than a dozen patients, all in the same unit at Henry Ford Hospital, contracted Salmonella last week.

The hospital is working with state officials to try to figure out the source of the outbreak, but so far, no one knows where it came from.

Usually Salmonella is associated with contaminated food, but that’s not the case in this instance. Officials say it does not appear to be a food-related issue. They are still trying to find the source of the Salmonella.

A spokesthingy for Henry Ford Hospital said in a statement, “There’s no evidence at this time that the illness is food related.”

Dr. Frank McGeorge said, “In a hospital setting, it could be just about anything, and that’s where the detective work happens and really has to take place.”