Health officials say a bad batch of oysters at an unnamed Chattanooga restaurant made seven people ill.

The illnesses were reported more than two weeks ago and state and federal officials are working to find where they were shipped and served.

The Food and Drug Administration and Tennessee Department of Health were warning people not to eat oysters from a particular section of West Karako Bay in Louisiana during the first three weeks of December.

Prestige Oyster Co. of Theriot, La., first shipped the oysters to Bon Secour Fisheries in Alabama, which then sent them to the Chattanooga restaurant.

The oysters contained norovirus, which can cause symptoms similar to stomach virus.