Fraser Valley/Vancouver _ Public health officials are alerting the public to take precautions following an increase in reports of gastrointestinal illness associated with eating raw oysters from British Columbia.
Between November 1 and December 18, 2024, 64 cases of norovirus-like gastrointestinal illness have been reported in the Vancouver Coastal Health, Fraser Health and Island Health regions. Those affected have reported symptoms of diarrhea, vomiting, and/or stomach pain after eating raw oysters from restaurants and retail locations. While some individuals have visited emergency departments, there have been no hospital admissions reported.
Norovirus is a common cause of gastrointestinal illness, especially during the winter months. Symptoms usually begin 12 to 48 hours after infection and can include nausea, vomiting, cramps, fever, and diarrhea. Symptoms can be intense (e.g., multiple episodes of vomiting in a short period of time) and generally last between 24 and 72 hours. Fluid loss or dehydration can be a serious problem for those who are very young and older adults. Norovirus spreads very easily from person to person but can also be caused by consuming food or water contaminated with the virus.
Oysters can become contaminated with norovirus that may be present in the marine environment where they are grown and harvested. The BC Centre for Disease Control and regional health authorities are reminding the public of risks associated with consuming raw or undercooked oysters, especially those who may be at higher risk of severe illness such as children, older adults or people who may be immunocompromised.
Food contaminated with noroviruses may look, smell and taste normal. To kill norovirus, you can cook oysters thoroughly, to an internal temperature of 90 degrees Celsius for 90 seconds before eating.
The BCCDC and regional health authorities are investigating illness reports in conjunction with federal partners. As part of this investigation, federal agencies have closed some areas to commercial shellfish harvesting, including areas in Baynes Sound, west of Denman Island. Fishery notices are available on the Department of Fisheries and Oceans Canada website. Those who harvest shellfish recreationally are advised to consult the BCCDC Shellfish map for site closures and to review Shellfish Harvesting Safety measures.
Food safety precautions when preparing shellfish
- Consume only cooked shellfish. Cooking will destroy viruses and bacteria and decrease the risk of gastrointestinal illness. To ensure adequate cooking, test shellfish with a probe thermometer and make sure the temperature reaches 90°C for 90 seconds.
- Wash your hands well with soap and water before and after handling any food.
- Keep cooking areas clean. Separate raw and cooked seafood to prevent cross-contamination and clean and sanitize knives and cutting boards. Clean hands frequently with soap and water or alcohol-based hand sanitizer.
- Do not consume oysters that do not open while cooking.
- Eat oysters right away after cooking and refrigerate leftovers.
If you are sick with gastrointestinal illness
- Use soap and water to clean your hands often. It is especially important to wash your hands after using the toilet or before handling food.
- Do not prepare foods for others.
- Most norovirus infections are mild and pass in a few days. Most people do not seek medical care.
- Dehydration is the most common complication. To prevent dehydration, drink plenty of fluids.
- Norovirus spreads easily from person to person. Anyone who is ill should avoid going to work, especially food handlers or caregivers, until at least 48 hours after symptoms have stopped.
- If you cannot maintain hydration due to excessive vomiting or diarrhea, or are otherwise concerned, call 811 or seek medical attention.
More information
- Information on norovirus https://www.healthlinkbc.ca/healthlinkbc-files/norovirus
- Commercial should check federal fishery openings and closures https://www.pac.dfo-mpo.gc.ca/fm-gp/shellfish-mollusques/contamination/index-eng.html
- Recreational harvesters should check the shellfish map for closures http://www.bccdc.ca/health-professionals/professional-resources/shellfish-harvesting-sites-status-map
The BC Centre for Disease Control, a part of the Provincial Health Services Authority, provides public health leadership through surveillance, detection, treatment, prevention and consultation services. The Centre provides diagnostic and treatment services for people with diseases of public health importance, and analytical and policy support to all levels of government and health authorities. The BCCDC also provides health promotion and prevention services to reduce the burden of chronic disease, preventable injury and environmental health risks. For more, visit www.bccdc.ca or follow us on Facebook or Instagram or @CDCofBC.
The Provincial Health Services Authority (PHSA) provides specialized health care services and programs to communities across British Columbia, the territories of many distinct First Nations. We are grateful to all the First Nations who have cared for and nurtured this land for all time, including the xʷməθkwəy̓əm (Musqueam), Sḵwx̱wú7mesh Úxwumixw (Squamish), and səlil̓w̓ətaɬ (Tsleil-Waututh) First Nations on whose unceded and ancestral territory our head office is located. We work in partnership with other B.C. health authorities and the provincial government to deliver province-wide solutions that improve the health of British Columbians. For more information, visit www.phsa.ca or follow us @PHSAofBC.
