As temperatures increase during the warmer months, toxins that are produced naturally by microorganisms in coastal waters can increase, and may accumulate in shellfish. Harmful toxins are most frequently found in mussels, clams, oysters, scallops, and crab, but can also be found in cockles, whelks, prawns, squid, and other species that feed on plankton. BC’s Drug and Poison Information Centre often sees an increase in calls during summer months for illnesses due to these types of toxins.
Eating contaminated shellfish can lead to serious illness including:
- Paralytic shellfish poisoning (PSP)
- Diarrhetic shellfish poisoning (DSP)
- Amnesic shellfish poisoning (ASP)
These illnesses can be life threatening, and shellfish contaminated with these toxins cannot be made safe by cooking.
Symptoms often begin minutes to hours after eating contaminated shellfish but can be experienced up to 24 to 48 hours later. Paralysis caused by shellfish toxins can be deadly.
If you feel tingling, numbness that spreads past the lips and mouth, increasing weakness, or difficulty walking or swallowing after eating shellfish, visit your nearest emergency room or call 9-1-1.
If you get diarrhea, vomiting and abdominal cramping after eating shellfish, call the Drug and Poison Information Centre at 1-800-567-8911, HealthLink BC at 8-1-1, or see a health care provider.
- Check for closures and advisories on the day you plan to harvest. Visit the BCCDC Shellfish Harvesting Status Map to find open and closed sites.
- Harvest on a receding tide when the tide is going out.
- Once you’ve harvested your shellfish, put them into a chilled cooler and keep them cold to prevent bacteria from growing.
- Only eat cooked shellfish. Cooking destroys viruses and bacteria and decrease the risk of gastrointestinal illness. To ensure adequate cooking, cook to an internal temperature of 90°C for at least 90 seconds.
- Do not cook crabs whole. Split them first and remove gut contents before boiling.
- Keep cooking areas clean. Separate raw and cooked seafood to prevent cross-contamination, clean and sanitize knives and cutting boards.
- Clean your hands before and after preparing food.
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 bccdc.ca or follow us on Facebook or Instagram.
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 @phsa.bc. -30-
Heather Amos
BC Centre for Disease Control
Provincial Health Services Authority
