The First Nations Health Authority and Island Health issued a public warning on March 22 after four confirmed cases of cholera on Vancouver Island linked to the consumption of herring eggs.

The outbreak is considered highly rare in Canada.

Health authorities are advising people not to eat herring eggs from French Creek to Qualicum Bay on the east coast of Vancouver Island. On March 23, the Department of Fisheries issued an emergency closure of herring egg harvest in the area.

The First Nations Health Authority stated in a news release that the cases are only related to herring eggs laid in marine environments, not herring roe harvested directly from fish.

Cholera can include symptoms such as mild to severe nausea, vomiting, severe diarrhea, muscle cramps, and rapid heart rate. Some individuals may become infected without symptoms. Bacteria can be passed between people, even from those who do not have symptoms.

Anyone who becomes ill is advised to visit a physician to confirm the cause of the illness and to receive treatment, and to inform healthcare providers if you have eaten raw or lightly cooked herring eggs within five days of the onset of the illness, or have been caring for someone who became ill after eating herring eggs. Frequent hydration with fluids is also advised. More information about cholera is available at the B.C. Centre for Disease Control website. 

Anyone who has herring eggs is asked to call the First Nations Health Authority Environmental Public Health Services at 250-924-6125 for testing of samples. (Freezing does not kill the bacteria.)

The bacteria is usually found in water or food sources that have been contaminated with feces by a person who has been infected with cholera, and it can be found in brackish water or coastal areas.

An investigation to determine the specific type of Vibrio cholera bacteria is still underway.