Update: Albertans reminded to cook shellfish to reduce risk of illness

April 27, 2018

EDMONTON – A recent increase in gastro-intestinal illnesses in the Edmonton Zone has prompted Alberta Health Services (AHS) to remind area residents of important precautions to reduce the spread of illness.

Fifteen cases (thirteen in Edmonton and two in Calgary) potentially linked to consumption of raw oysters from British Columbia are under investigation.

In the last week, the Public Health Agency of Canada has seen a decrease in the number of cases being reported to the outbreak investigation team which indicates the outbreak may be slowing. The outbreak investigation remains active and findings to date have identified that most people who became sick were infected after consuming oysters that were harvested in the south and central parts of Baynes Sound, British Columbia. The investigation into a specific source of contamination impacting the shellfish farms in that area is ongoing.

To reduce risk of illness, AHS advises:

  • Ensure oysters are fully cooked before consuming them. Lightly cooking oysters does not kill norovirus. Oysters need to be cooked to an internal temperature of 90° Celsius (194° Fahrenheit) for a minimum of 90 seconds in order to kill norovirus.
  • Discard any oysters that did not open while cooking.
  • Eat oysters right away after cooking and refrigerate leftovers.
  • Always keep raw and cooked oysters separate to avoid cross-contamination.
  • Do not use the same plate or utensils for raw and cooked shellfish, and wash counters and utensils with soap and warm water after preparation
  • Wash your hands well with soap before handling any food. Be sure to wash your hands, cutting boards, counters, knives and other utensils after preparing raw foods.

Illnesses associated with raw oysters or shellfish contaminated with viruses or bacteria commonly cause vomiting, watery diarrhea and abdominal cramps. Other symptoms can include nausea, fever, headache and bloody stools.

Although anyone who consumes raw shellfish is at risk of illness, people with weakened immune systems, young children, pregnant women and older adults are at increased risk for developing complications if they get sick.

Individuals who do develop these symptoms within 10 to 50 hours of eating raw shellfish are advised to contact Health Link at 811 to report the illness.

As with most gastro-intestinal illnesses, symptoms typically last for one day to a week and usually do not require any treatment; however, any Albertan whose symptoms persist or become more severe should visit a doctor.

The cluster of gastro-intestinal illnesses currently under investigation experienced onset of symptoms between March 15 and April 26. The type of illness has not been lab-confirmed. This is the second outbreak investigation into illness linked to consumption of raw oysters, in Alberta, in the past two years. In 2017, a similar outbreak was declared and Alberta completed an investigation that confirmed 42 cases in the province were linked to consumption of raw oysters.

For more information about shellfish food safety visit: http://healthycanadians.gc.ca/eating-nutrition/healthy-eating-saine-alimentation/safety-salubrite/meat-viandes/shellfish-mollusques-eng.php.

Alberta Health Services is the provincial health authority responsible for planning and delivering health supports and services for more than four million adults and children living in Alberta. Its mission is to provide a patient-focused, quality health system that is accessible and sustainable for all Albertans.

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For media inquiries, contact:

Kristin Whitworth
AHS Communications