Ken Falk, President of Fraser Valley Duck and Goose Ltd., lost 140,000 birds in the outbreak of a bird flu in Canada's western province of British Columbia in 2004. Now he is bracing for another possible hit to his family-owned business.

Falk's farm remains under quarantine a day after one of his 60,000 ducks tested positive for the H5 strain of bird flu.

Officials from the Canadian Food Inspection Agency (CFIA) are visiting farms in a five-km radius around the duck and goose farm in the town of Chilliwack in southern British Columbia. They are warning bird owners to practise strict biosecurity.

Swab samples from the infected ducks are on their way to a national health research center in Winnipeg, which houses one of the world's most secure labs for the testing of deadly diseases, for further testing. It will take two days of tests to determine if it is the same type that has infected humans in Asia.

On Saturday, local reports say the CFIA will order the cull of all birds on Falk's farm, meaning a precautionary killing of Falk's birds.

"We have to do something to ensure this H5 strain doesn't mutate and get into the environment," Cornelius Kiley with the CFIA told CTV.

"Obviously we're very sad about that. And it's going to be hard but as an industry, we've decided to be proactive," Falk said.

According to Saturday's Vancouver Sun, the virus showed up after Falk sent a sample of birds from his farm to a government lab to be tested for something unrelated to avian flu.

Since the 2004 outbreak, he said, poultry farmers in British Columbia have introduced increased bio-security measures to the industry to screen for the virus.

News that the virus has once again turned up, he said, was disappointing, but not altogether surprising.

"Waterfowl are known to harbor influenza viruses of various subtypes. This is not surprising that we find this in ducks. When you look for it, then you find it," said Falk, who has 55 employees on the farm.

The provincial officials said they were not sure which strain of the H5 avian bird flu is in the ducks this time, but were quick to stress there is no risk to human health.

In another development, wild birds in the central province of Manitoba have tested positive for a low-pathogenic subtype of the H5N1 avian flu virus. However, the strains were from the family of North American H5N1 viruses, not the forms 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," said Brian Evans, CFIA's Chief Veterinary Officer, on Saturday.

"From a genetic perspective, there are significant strain differences in their structure," he said.

Officials also confirmed that two birds in British Columbia carried H5N9 viruses and five carried H5N2. Two birds in Quebec carried H5N3 viruses. All were "low-path" viruses, meaning they aren't very dangerous to waterfowl and other birds.

The viruses were isolated as part of a cross-country surveillance program to find what avian flu viruses are being carried by wild ducks in Canada.

The results came more than two weeks after officials first announced that birds in British Columbia, Quebec, and Manitoba were found to be carrying avian flu strains.

"Finding only low pathogenic avian influenza means that these viruses would cause only mild disease, if any at all, if introduced into domestic birds," Evans said.

North American H5N1 viruses have so far proven to be much milder viruses than their distant Asian counterparts, avian influenza experts say.

"We've got 32 years of surveillance work that says these North American strains in wild birds in the past have never been a threat, " Dr. Richard Slemons, an avian influenza expert at Ohio State University, told The Canadian Press.

"Does that mean they won't be a threat in the future? No, it does not. But history says they aren't a risk."

There are many influenza subtypes, two of which include H5 and H7. To date, the H5N1 strain has proven the most deadly to humans, infecting 117 people, mainly in Asia, and killing about 50 percent of them.

In 2004, a highly pathogenic strain of H7 - H7N3 - was detected in chickens in the Fraser Valley and led to a mass culling of 17 million chickens, turkeys, geese and ducks on the CFIA's orders.

The H7N3 strain was fatal to birds but posed little or no risk to humans.

Source: Xinhua