More B.C. oysters linked to illnesses

The Canadian Food Inspection Agency is warning consumers to avoid eating raw oysters from a third B.C. processor.

West Coast oysters have been linked to at least three clusters of a norovirus-type illness in the Vancouver area.

CFIA is warning consumers to avoid eating Pacific Rim Shellfish petite raw oysters. Last week it issued a similar advisory about Effingham extra small raw oysters processed at Albion Fisheries and Sea World Fisheries in Vancouver.

The Pacific Rim oysters come from lot numbers 1091501 and 1092204. However many of the oysters were sold to restaurants and various retail outlets, so original lot numbers may not be available.

According to the B.C. Centre for Disease Control, one of the agencies investigating the outbreak, there have been three outbreaks where people have been stricken with diarrhea and other intestinal symptoms after eating raw oysters at restaurants or other events.

Most of the people showed symptoms within 48 hours of eating the raw oysters, and recovered in one to two days.

The suspected cause of the illness is norovirus, which causes gastroenteritis, often referred to as stomach flu.While norovirus normally spreads from person to person, oysters can be carriers of it if they are contaminated by sewage in the water before they are harvested.

Because oysters feed by filtering large volumes of water through their gills there can be an accumulation of the virus in the flesh and gut of the oyster. Viruses cannot be removed from oysters through cleaning.

The BCCDC advises that thorough cooking can kill the virus, if theoysters are heated to an internal temperature of 90C before being consumed.