British Columbia oysters are now linked to dozens of norovirus cases in several US states

Health officials in the United States say an outbreak of norovirus linked to raw oysters from British Columbia has spread to at least 13 states.

A statement released by the Centers for Disease Control and Prevention indicates that at least 91 illnesses are linked to the consumption of potentially contaminated oysters.

States reporting norovirus cases range from Washington, Oregon, California and Hawaii east to New York and Florida.

The CDC and the US Food and Drug Administration say they are still trying to determine the extent of distribution and the size of the outbreak.

The Public Health Agency of Canada says shellfish, harvested off the east coast of Vancouver Island, are linked to at least 279 illnesses, most in British Columbia, 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 ordered not to serve or sell the oysters, and the CDC has extended that advice to U.S. restaurants and fish stores.

Health officials say norovirus symptoms can include diarrhea, vomiting, nausea and stomach cramps.

No deaths related to this outbreak have been reported.