Avian Flu Found on B.C. Farm Not Lethal Strain but Cull to Proceed

By TERRI THEODORE

ABBOTSFORD, B.C. (CP) – The avian flu discovered on a B.C. poultry farm is not a lethal variety, but about 60,000 birds on the farm will still be destroyed as a precaution, public health officials said Sunday.

The Canadian Food Inspection Agency says the infection at the duck and goose farm in Chilliwack, near Vancouver, is different from the virulent outbreak among birds in Asia.

Veterinarian Cornelius Kiley said the H5 virus found in the commercial duck is a low pathogenic North American strain.

“This confirmation means we’re looking at a virus capable of causing only a mild disease (in birds), if any at all,” said Kiley, who works for the food inspection agency.

Federal officials separately reassured Canadians on the weekend that the strain of the flu found in B.C. and positive test results for the H5N1 avian flu virus found in two wild ducks in Manitoba as part of a new surveillance program pose no threat to human health.

On Saturday, officials said the H5N1 avian flu viruses found in the wild ducks is not the dangerous form of the virus circulating in Southeast Asia.

“I want to emphasize that the H5N1 subtype detected in Manitoba is completely distinct from the strain currently present in Asia,” Dr. Brian Evans, Canada’s chief veterinary officer, said in disclosing the findings.

“The identification of this virus, which has been previously identified in North American birds, poses no new risks to human health,” added Dr. Arlene King, head of respiratory diseases for the Public Health Agency of Canada.

Avian flu viruses bearing the same subtype name can vary widely in their ability to cause disease in poultry or pose a human health threat.

Officials announced Friday that they had found the duck with the H5 avian flu virus on the farm in B.C.

The 60,000 birds on the farm, mostly ducks, will be slaughtered as a precaution while four other farms in the area have been placed under quarantine.

The cull will be in line with a response plan set up after an outbreak of avian flu in the Fraser Valley in 2004 in which about 17 million birds had to be destroyed.

Kiley said killing the birds in Chilliwack is necessary because the virus could change.

“The whole secret is to prevent these fairly innocuous viruses in wildlife from being transmitted to commercial operations. Because in commercial farms we know that these viruses can change,” Kiley said.

“We know now that it’s low pathogenic but at the beginning of the outbreak last year it began as a low pathogenic virus. That particular virus changed to high pathogenic.”

Gillian Arseneault, medical health officer for the Fraser Health Authority, agreed with Kiley at the news conference.

“This is the biosecurity equivalent of buckling up your seat belt when you get in your car to drive,” Arseneault said. “It is preventing a problem before it even has a chance to start.”

Arseneault noted that the virus found at the farm isn’t a threat to people.

“There is absolutely no increase in risk to human health,” Arseneault added. “This is a virus that has been in our birds for a kazillion years, and backyard flocks are out there mingling, so the virus will be mingling with them too.”

By conducting the cull, it reduces the chances of the virus changing.

“If we allowed these viruses . . to get into big commercial flocks and to reproduce without limit, you’re increasing the chance that sooner or later one of them is going to turn bad,” Arseneault explained. “That’s why I say this is pure prevention.”

The H5N1 viruses in Manitoba were isolated from two ducks as part of a first-ever cross-country surveillance program aimed at taking a snapshot of what flu viruses wild ducks are carrying.

H5N1s have been found previously in North America, mostly recently in domestic poultry in Michigan in 2002, Evans said.

He said viruses carried by birds that follow migratory flyways through North, Central and South America are typically genetically distinct from those found in Europe and Asia – and that is the case with these viruses.

Where the Asian H5N1 viruses are highly pathogenic, the North American viruses typed so far through the surveillance program are all viruses of low pathogenicity, he added.

Other H5 viruses have also been identified as part of the surveillance program, Evans noted.

Two birds in British Columbia carried H5N9 viruses and five carried H5N2s. Two birds in Quebec carried H5N3 viruses. All were low-path viruses.

Analysis of the viruses carried by birds sampled in Quebec, Manitoba and British Columbia have been completed, he said. Findings from Ontario, Alberta, New Brunswick and Nova Scotia have yet to be reported.