Shellfish may accumulate bacteria (Vibrio parahaemolyticus), viruses (norovirus, hepatitis A), and toxins (paralytic shellfish poisoning, diarrhetic shellfish poisoning) or other impurities present in the water. Thorough cooking destroys bacteria and viruses, but does not destroy toxins.
To date in 2012, five cases of locally-acquired Vibrio parahaemolyticus infection have been reported. In 2011, 42 cases of vibrio were reported. These illnesses have been linked to raw shellfish served in restaurants, bought at retail, or self-harvested in communities throughout the province including, Gibsons, Sechelt, Powell River, Ladysmith, Qualicum, Ucluelet, Gabriola Island, Cortes Island and Parksville.
In addition to individual cases, BC has also experienced outbreaks associated with shellfish. In 2010, an outbreak of norovirus from raw oysters affected over 30 people and in 2011 more than 60 people became ill after consuming cooked mussels contaminated with diarrhetic shellfish poisoning.
Satefy tips to reduce the risk of all shellfish-related illnesss:
- Purchase shellfish ONLY from approved sources. All bivalve shellfish sold in British Columbia must come from a federally approved source, and outlets and restaurants selling them must be able to provide a shellfish shipper’s tag, which ensures federal inspection.
- Consume only cooked shellfish. Cooking will destroy viruses and bacteria and decrease the risk of gastrointestinal illness. When cooking shellfish at home, ensure shellfish are kept in a cold environment at all times, use drinking-quality water to rinse ready-to-eat shellfish, and ensure adequate cooking time. To ensure adequate cooking, test oysters with a meat thermometer and make sure the temperature reaches 90°C (195°F) for 90 seconds. This will kill the vibrio bacteria and minimize the risk of other infections.
- Do not cross-contaminate when handling raw and cooked seafood. Prevent cross-contamination by storing raw and cooked seafood separately, cleaning and sanitizing knives and cutting boards and working with clean hands.
- Obey posted warnings and bans when self harvesting shellfish. To check if a shellfish area is open for harvesting call the Department of Fisheries and Oceans toll-free at 1-866-431-3474.
Anyone becoming ill with diarrhea and vomiting after eating shellfish should report their illness to their local public health office or primary care provider and see a physician if symptoms persist or become severe. Call the 24-hour HealthLink BC Line at 8-1-1 for more information.
BCCDC, an agency of the Provincial Health Services Authority, provides provincial and national leadership in public health through surveillance, detection, treatment, prevention and consultation services. The centre provides both direct 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.