The Louisiana Department of Health closed an oyster harvesting area after 15 people reported norovirus-like illnesses.

The U.S. Food and Drug Administration is warning retailers and restaurants not to sell certain oysters that could be contaminated with norovirus after 15 people became ill in Louisiana, U.S.A.

The department said the Louisiana Oyster Task Force and local harvesters were notified of the closure on Tuesday, and that it’s working with the Department of Wildlife and Fisheries to ensure no oysters are harvested from the area for at least 21 days. Oysters from other parts of Louisiana are safe to eat, the department said.