Health officials in British Columbia are warning the public about a spike in cases of norovirus linked to eating raw B.C. oysters.
In a bulletin issued Friday, Vancouver Coastal Health said 50 people had presented with acute gastrointestinal illness since Monday, after eating the shellfish raw.
The health authority said norovirus had been confirmed through testing in some of the cases, and was suspected in others.
Symptoms of norovirus can include nausea, cramping, chills, fever, stomach pains, diarrhea and vomiting, and generally occur within 12-48 hours of consumption of affected shellfish.
The virus can be killed by cooking oysters to an internal temperature of 90 C (194 F), for 90 seconds before eating.
Health officials have not limited the sale of raw oysters, but the B.C. Centre for Disease Control issued a notice to businesses that sell them Friday with recommendations on how to reduce risk.
The BC CDC, local and federal officials and the shellfish agency are investigating, and “affected harvest areas are being closed and will reopen when contamination is cleared,” Vancouver Coastal Health said.
In 2016 and 2017, more than 400 people across Canada fell ill after eating raw B.C. oysters. The BC CDC later said it believed the outbreak was linked to norovirus in sewage carried by ocean currents, combined with cold weather that helped the virus to survive.
Anyone who becomes ill after eating oysters is being asked to report it to Vancouver Coastal Health at (604) 675-3800 or by e-mail to EHVC@vch.ca.