Health officials in the United States say a norovirus outbreak linked to raw British Columbia oysters has spread to at least 13 states.
A statement posted by the Centers for Disease Control and Prevention says at least 91 illnesses are related to consumption of the potentially contaminated oysters.
States reporting norovirus cases range from Washington, Oregon, California and Hawaii east to New York and Florida.
The CDC and U.S. Food and Drug Administration say they are still trying to determine the extent of the distribution and the size of the outbreak.
The Public Health Agency of Canada says the shellfish, harvested off the eastern coast of Vancouver Island, is linked to at least 279 illnesses, most in B.C., but cases have also been recorded in Ontario, Alberta and Saskatchewan.
Four food recalls were issued in Canada between February and March with retailers and restaurants told not to serve or sell the oysters, and the CDC has extended that advice to U.S. restaurants and fish shops.
Health officials say norovirus symptoms can include diarrhea, vomiting, nausea and stomach cramps.
No deaths from this outbreak have been reported.