Canadian norovirus outbreak linked to oysters

By Joseph James Whitworth

- Last updated on GMT


Related tags Epidemiology Health care Gastroenteritis

More than 200 people have been sickened by norovirus in three Canadian provinces linked to raw/undercooked oysters.

The Public Health Agency of Canada (PHAC) is investigating gastrointestinal illnesses in British Columbia, Alberta and Ontario.

Public health partners in these provinces have linked cases to eating oysters from British Columbia.

Norovirus confirmation

Although not all cases have been tested, norovirus infection has been confirmed in some of them.

Shellfish like oysters may be contaminated by sewage in water before they are harvested.

Cases are from British Columbia (143), Alberta (35) and Ontario (24) and individuals became sick between December and January.

Illnesses can be avoided if oysters are cooked to an internal temperature of 90° Celsius/194° Fahrenheit for a minimum of 90 seconds and hand washing and food safety practices are followed.

Oysters that do not open when cooked should be discarded.

Noroviruses are very contagious and can spread easily from person to person.

People usually develop symptoms of gastroenteritis within 24 to 48 hours but they can start 12 hours after exposure.

It is the first outbreak investigation into illness linked to raw oysters in Alberta since 2015, when 19 cases of Vibrio parahaemolyticus infection were linked to them.

Ontario investigation

Dr David McKeown, Ontario's acting chief medical officer of health, said a rise in illness may be associated with oysters from British Columbia.

"Since January 2017, 24 cases of gastrointestinal illness consistent with norovirus have been reported in Ontario from individuals who reported eating raw or undercooked oysters,” ​he said.

“Foodborne outbreaks of norovirus illness can occur when food is contaminated with the virus. Shellfish such as oysters can become contaminated from the water before they are harvested.

“The common symptoms of gastrointestinal illness are nausea, vomiting, diarrhea and stomach cramps. In most healthy people, acute diarrhea and vomiting should resolve in one to two days.

“Symptoms may last longer in some people. Anyone experiencing these symptoms after eating oysters should seek the advice of their health care provider."

An outbreak of norovirus in oysters is also ongoing in New Zealand with 11 people ill.

Earlier this year, France reported an outbreak from oysters in the south of the country and late last year Netherlands noted cases from oysters imported from a different region in France.

Related topics Food safety and labeling

Related news

Related products

show more

Sustainable Sweetening Solutions from ADM

Sustainable Sweetening Solutions from ADM

Content provided by ADM | 13-Oct-2023 | Product Brochure

ADM understands sweetness—and sustainable sourcing. Not only do we have the industry’s most comprehensive portfolio of sweetening solutions, we also are...

 Four actionable steps to reduce allergen recalls

Four actionable steps to reduce allergen recalls

Content provided by FoodChain ID | 04-Oct-2023 | White Paper

Failing to mitigate allergen risks has serious consequences - not just for consumer safety, poor allergen procedures can also cause financial losses and...

Accelerate your new product development (NPD)

Accelerate your new product development (NPD)

Content provided by FoodChain ID | 02-Oct-2023 | White Paper

Delivering new products to market is a complex process with multiple challenges that results in a failure rate of between 30-40%.

Injection Molding Solutions: Key Considerations

Injection Molding Solutions: Key Considerations

Content provided by Husky Injection Molding Systems Ltd. | 27-Sep-2023 | Insight Guide

Food and consumer packaged goods (CPG) producers are now facing a number of new challenges and opportunities.

These include the rising adoption...

Related suppliers

Follow us


View more