A recent salmonella outbreak with no known food source has more than doubled in infections in over a week.

On Sept. 15, the Centers for Disease Control and Prevention reported 127 people in 25 states had been infected with salmonella, resulting in 18 hospitalizations. On Thursday, the CDC announced the number of reported illness had more than doubled: 279 people have been sickened, and the outbreak has reached another four states. An additional eight people have now been hospitalized because of salmonella.

On Sept. 2, 20 people were reported sick by the strain of Salmonella Oranienburg. Since then, the CDC says the outbreak has “grown rapidly.”

No food source has been attributed to the outbreak, but state and local officials from infected states have collected food samples from…