Canadian Raw Oysters Are Behind a Norovirus Outbreak in California

Raw Canadian oysters are likely behind a norovirus outbreak that has both Canadian and American health officials warning consumers to use caution.

The California Department of Public Health on Tuesday said that approximately 100 people there have become sick after eating oysters from Baynes Sound in British Columbia. The department said several people have tested positive for norovirus, a highly contagious infection that causes inflammation of the stomach and/or intestines and results in symptoms including vomiting, diarrhea, nausea, fever and stomach pain.

Get our Health Newsletter. Sign up to receive the latest health and science news, plus answers to wellness questions and expert tips.

Please enter a valid email address.

* The request timed out and you did not successfully sign up. Please attempt to sign up again.

Sign Up Now

An unexpected error has occurred with your sign up. Please try again later.

Check here if you would like to receive subscription offers and other promotions via email from TIME group companies.

You can unsubscribe at any time. By signing up you are agreeing to our Terms of Service and Privacy Policy.

Thank you!

For your security, we've sent a confirmation email to the address you entered. Click the link to confirm your subscription and begin receiving our newsletters. If you don't get the confirmation within 10 minutes, please check your spam folder.

Nearly 200 people in Canada have reported gastrointestinal illness associated with the outbreak, and multiple people there have tested positive for norovirus, according to the Public Health Agency of Canada.

The Food and Drug Administration (FDA) on Wednesday also warned consumers that the problem may extend beyond California and Canada. The agency has confirmed that the potentially tainted oysters were also distributed to Alaska, Illinois, Massachusetts, New York and Washington, and warn that they may have reached other states as well. The FDA is urging retailers and consumers not to serve or eat oysters that were harvested in four locations within Baynes Sound.

The FDA is working with state health departments to remove the affected oysters from the market, according to the announcement. The farms associated with the outbreak have been closed during the investigation.

Write to Jamie Ducharme at jamie.ducharme@time.com.