Migratory birds suspected in B.C. avian flu cases

VANCOUVER, B.C. — Three of four of the latest avian-flu outbreaks in Canada have been in the Fraser Valley, possibly because of the region's popularity with migratory waterfowl, experts say.

In the latest outbreak, that H5 strain of the virus was detected in some turkeys on a property owned by two brothers in January, and 60,000 turkeys were culled on an Abbotsford farm last week.

Tests indicate the virus has not spread to any other poultry producers within a quarantine zone of about two miles, but the Washington Department of Agriculture increased tests for the virus at 13 farms in Whatcom County, a few miles to the south, as a precaution.

Washington has never had a confirmed case of bird flu, even in 2004, when the Fraser Valley was hit by a highly contagious H7-type flu. About 15 million birds, almost the entire poultry population in the valley, were destroyed.

In the second Fraser Valley outbreak, two duck farms were infected with the H5N2 strain of the virus in November 2005.

Canada's only bird-flu outbreak outside the region was in 2007, when a highly pathogenic H7N3 strain was found in Saskatchewan on a farm that produced hatching eggs to raise broiler chickens.

Ronald Lewis, the province's chief veterinary officer, and Sandra Stephens, veterinary-program specialist with the Canadian Food Inspection Agency, suspect the culprits in British Columbia are mainly migratory birds.

"We're on the Pacific flyway, so there are lots of birds passing through every year," Lewis said, "and we know wild waterfowl carry a variety of different strains of avian influenza."

In addition, people can easily walk over the areas where wild waterfowl have been, Lewis added, "and we know avian influenza has some capability of aerosol transmission."

Avian-influenza virus is prolific, and when wild waterfowl have it "they shed tremendous numbers of viral particles," Stephens said. "All these birds, when they get to their summer or wintering grounds, they co-mingle."

Nor are North America's flyways altogether isolated, she added.

"Although you tend to think of the North American flyways as being separate from Europe and Asia, in fact there is some crossover in the northern breeding grounds," Stephens said.

The concentration of commercial-poultry producers in the Fraser Valley is also a factor in the outbreaks, she added.

Although any poultry producer can be exposed to migratory birds, "where we have more concerns are areas like the Fraser Valley or the Niagara Peninsula where there are large concentrations of poultry farms close together," she said.

Calvin Breukelman, of the British Columbia Poultry Association, estimates there are about 600 poultry producers in the Fraser Valley, an industry worth close to $1 billion Canadian, chiefly because of the proximity to Vancouver.

"In an ideal world, we of course wouldn't have this concentration, but it's not ideal and we have to do whatever we can to reduce the impact of that concentration," Lewis said.

Despite the outbreaks, Lewis said it was highly unlikely the region would be hit with the highly pathogenic H5N1 virus that killed hundreds of people in Asia, Africa and Europe.

"We don't have that kind of proximity [of large numbers of humans] to wild and commercial ducks, cohabiting in many cases, that is present in those countries," he said.

He also cited prevention measures adopted by Canada after the 2004 outbreak. He estimated industry compliance at about 98 percent.

Initial testing for avian viruses can now be done in Abbotsford, "so we have eliminated the delays in having to ship samples for testing at the federal lab," Lewis added.

Fraser Valley poultry producers are awaiting tests to determine how contagious the virus in the latest outbreak may be.

Results may be weeks away, Stephens said.