Unheard-of cholera cases on Vancouver Island linked to B.C. herring eggs

The First Nations Health Authority and Island Health are warning the public not to eat herring eggs after linking the food source to at least four cases of cholera on Vancouver Island.

Island Health admits the outbreak caught them off guard. The disease, usually associated with the tropics, is extraordinarily rare in Canada.

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In a statement late Friday, the health authority said that herring eggs found on kelp, seaweed and other surfaces from the French Creek to Qualicum Bay area have been associated with the outbreak. The federal Department of Fisheries and Oceans has ordered an emergency closure of herring egg harvest in the area.

All patients thus far are First Nations individuals who had consumed herring eggs, said Island Health. The disease was identified when stool cultures from the patients came back positive for the vibrio cholerae bacteria, whose natural habitat is brackish or salt water, but normally found in tropical waters.

The bacteria can cause the intestinal illness cholera, which may include mild to severe nausea, vomiting, and very severe, watery diarrhea. 

Cholera is easily treated. According to the B.C. Centre for Disease Control, the treatment for cholera is simple rehydration with clean drinking water. In some cases, antibiotics are administered. But, left untreated, the disease can cause rapid and extreme dehydration, leading to kidney failure and death.

Cholera affects three to five million people worldwide and causes over 100,000 deaths annually, but it is rare in industrialized countries like Canada, which has averaged just two cases a year since 2014, according to the World Health Organization. Furthermore, most cases in Canada result from international travel to an affected region.

Island Health is calling the bacteria’s discovery in island waters a “unique situation” and taking the situation very seriously.

The investigation into these cholera cases continues, the health authority said, and is being conducted in collaboration with B.C. Centre for Disease Control and First Nations communities. This includes the testing of sea water and leftover food samples. 

Health authorities recommend:

• No consumption of herring roe harvested from French Creek to Qualicum Bay from kelp, seaweed or other surfaces.

• If you are ill, keep hydrated by drinking small amounts of fluid frequently. Let your health-care provider know that you have eaten raw or lightly cooked herring eggs within five days of the onset of illness.

• As the bacteria can be passed from one person to another even if you don’t have symptoms, always wash your hands after going to the bathroom or caring for someone who has been ill.

• If you have stored herring eggs, call the First Nations Health Authority environmental public health services at 250-924-6125.

• Discard any stored herring eggs. Freezing does not kill the bacteria.

• When handling herring eggs, wash your hands and sanitize dishes and equipment to avoid cross contamination.

• Ensure other community members who might have received herring eggs are aware of the proper precautions.

• A sanitary shellfish closure exists for bivalves in the French Creek-Qualicum Bay area. Harvesters are reminded to check for closures prior to harvesting.

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