2 B.C. oyster farms closed after norovirus outbreak

The B.C. Centre for Disease Control says since March about 40 cases of acute gastrointestinal illness have been connected with the consumption of raw oysters.

40 cases of gastrointestinal disease linked to eating the shellfish raw

The consumption of raw oysters has once again been linked to an outbreak of norovirus in B.C. (Elaine Thompson/Associated Press)

Two B.C. Vancouver Island oyster farms have been closed following an outbreak of norovirus associated with eating the raw shellfish.

The B.C. Centre for Disease Control says about 40 cases of acute gastrointestinal illness have been connected to the consumption of raw oysters since March. Testing has confirmed some of the cases were norovirus.

Federal officials with Fisheries and Oceans Canada (DFO) confirmed the affected farms are located on the east coast of Vancouver Island at Deep Bay and Denman Island.

While the two farms are no longer harvesting oysters for consumption, no recall of oysters has been issued by the Canadian Food Inspection Agency.

Human sewage suspected

While the precise sources of contamination have not been identified, human sewage in the marine environment is currently believed to be the most plausible cause of shellfish contamination, according to BCCDC epidemiologist Marsha Taylor.

Anyone who falls ill with diarrhea and vomiting after eating shellfish should call B.C. HealthLink at 811 where qualified personnel can help you evaluate your symptoms, said Taylor. Most people recover from norovirus on their own with proper hydration and rest, but in some cases dehydration can be severe and require medical attention.

In order to kill norovirus and other pathogens, the BCCDC recommends consumers cook oysters thoroughly, to an internal temperature of 90 C for 90 seconds. Consumption of raw oysters is not encouraged.

Widespread impact

The president of the B.C. Shellfish Growers Association noted that while only two farms were closed, the entire industry will likely be hit by the impact.

 "The problem with these general advisories is, rather than target the farm that may have a problem, a lot of industry has to suffer the consequences from a depressed market," he said.

In late 2016 and early 2017, more than 400 norovirus cases associated with raw or undercooked B.C. oysters led to the closure of 13 farms.

That outbreak was declared over in April 2017. Human sewage was also suspected as the cause.

"Is there a solution? Yes, we need to pay more attention to what we are putting into the ocean," said Pocock.