Research ties ocean currents to norovirus outbreak at B.C. oyster farms
VANCOUVER — Researchers with the BC Centre for Disease Control may have pinpointed how a mysterious norovirus outbreak spread, forcing the closure of 13 West Coast oyster farms and curtailing operations at others as hundreds of Canadians fell ill.
An article published in the latest edition of the British Columbia Medical Journal says sewage is often the cause of ocean contamination and contaminants spread by currents affected oyster farms on the east and west coasts of Vancouver Island.
Researchers determined the norovirus outbreak began last November and made more than 400 people sick across Canada by March, but investigators were initially uncertain how a single source of the illness could affect such a huge area.
The article says it’s still unclear if one or many sewage sources were involved, but a wet fall and unseasonably cold winter could have enhanced norovirus survival and allowed oysters to retain tainted ocean sediments longer than usual.