Seven cases of salmonella have been confirmed in people who attended a Memorial Day weekend concert at the Gorge Amphitheater, the Grant County Health District announced Friday.

Three cases came from Washington state and four from British Columbia. The cases stemmed from the Sasquatch Music Festival. No cases are associated with the Tom Petty concerts held about two weeks later on June 11-12.

The county health district is working on an investigation with the state Department of Health and British Columbia Center for Disease Control.

Health district food inspectors were at the amphitheater Friday during the Lilith Fair to monitor food handling practices.