The BC Centre for Disease Control says more than 70 people have become ill from eating oysters that may have been raw or improperly cooked in homes or restaurants.
The centre says the outbreak has occurred in various parts of the province and more cases are expected.
Dr. Eleni Galanis, an epidemiologist at the centre, says testing in several cases confirmed the presence of norovirus, and the illness is suspected in the other cases.
She says norovirus and other bugs can be killed by cooking oysters to an internal temperature of 90 C for 90 seconds.
Galanis says in a release that eating oysters during the summer is linked to a higher risk of illness from naturally occurring bacteria, but other microorganisms such as norovirus can be present all year.
Anyone who becomes sick with diarrhea and vomiting after eating oysters is advised to call BC HealthLink at 811, and people with severe or persistent symptoms should see a doctor.