Imagine you take a bite of a freshly harvested mussel or clam and immediately your mouth begins to tingle. As you continue eating, the feeling doesn’t go away; in fact, it intensifies. Soon your whole mouth is numb, and now your face and neck are tingling too.
If this happened, would you know what was causing your symptoms?
Tingling in the lips, mouth or hands can be the first signs of paralytic shellfish poisoning, a life-threatening condition caused by eating shellfish, usually clams and mussels, and rarely crabs, that have been contaminated with toxins during algae blooms. Paralytic shellfish poisoning causes temporary paralysis, and in severe cases, makes it difficult or impossible to breathe without assistance.
The toxins that cause paralytic shellfish poisoning can occur anywhere in coastal B.C. BCCDC’s shellfish harvesting status map provides up-to-date information on which areas are safe for harvesting and which are closed.
There’s a common misconception that you can’t get paralytic shellfish poisoning in the fall and winter months. In fact, some of the most serious recent cases of paralytic shellfish poisoning in B.C. occurred in the fall and winter.
In the last three years, BC Centre for Disease Control Environmental Health has received calls on nine separate paralytic shellfish poisoning incidents affecting 15 individuals. These cases occurred in areas across coastal B.C.
One person experienced total body paralysis and lost the ability to breathe. Without immediate medical care this patient would have died.
Tingling around the mouth while or just after eating shellfish is an early sign of paralytic shellfish poisoning.
If you do experience tingling in your mouth or hands while or just after eating shellfish, stop eating, call 911 or Poison Control (1-800-657-6911), and freeze a sample of the shellfish you have been eating for testing.
The most severe illnesses in B.C. occurred when shellfish was harvested recreationally by individuals in closed areas.
The people who became ill ate a variety of shellfish: clams, butter clams, oysters, mussels and in one case, crab meat.
The regulatory limit for the toxins that causes paralytic shellfish poisoning is 80 micrograms per 100 grams of shellfish; toxins levels in some of the foods eaten by people who got sick ranged from more than twice the limit to 250 times the limit.
How to prevent paralytic shellfish poisoning
Check the map: BCCDC’s shellfish harvesting status map provides up-to-date information from Fisheries and Oceans Canada about which areas are open for shellfish harvesting. If an area is marked as closed, do not harvest there.
Know the signs: Symptoms of paralytic shellfish poisoning include tingling and numbness that spreads from the mouth and face to the neck and limbs, dizziness, arm and leg weakness, difficulty breathing, headache, nausea and vomiting. If you experience these symptoms within a few minutes to hours of eating shellfish, call 911, the poison control line (1-800-657-8911) or go to hospital immediately.
Know your source: When purchasing shellfish, buy from reputable suppliers and check for a tag verifying federal inspection. If you’re given shellfish that someone else harvested, make sure it was harvested from an area that is open for shellfish harvesting.
Read more about paralytic shellfish poisoning here.