Canadian veterinary officials said on Thursday they have found the H7N3 strain of avian influenza on a Saskatchewan chicken farm, but noted the case was not the highly pathogenic H5N1 strain seen elsewhere.
"This virus is not the same as the strain circulating in Asia, Africa and Europe, which has been associated with human illness. H7N3 is not normally associated with serious human illness," the Canadian Food Inspection Agency said in a statement.
The affected birds were not destined for immediate slaughter and were not producing eggs for human consumption, the agency said.
It acknowledged that the discovery would likely lead other countries to temporarily bar Canadian chicken exports — the United States and the European Union are the two largest importers of Canadian poultry, most which is produced for the domestic market.
"It is a mild strain. It doesn't appear to be a big deal," said Paul Aho, an industry consultant with Poultry Perspective. Some countries might ban Canadian chicken, but Aho said even that should not be a concern because Canada does not export much chicken.
Saskatchewan, known for its large expanses of grain fields, accounts for a small fraction of Canadian poultry production.
45,000 chickens to be killed
CFIA said the farm had been placed under quarantine and all 45,000 chickens will be destroyed.
The H7N3 strain is routinely found in a low-pathogenic form in wild ducks in North America, said Jim Clark, a senior official with the CFIA. The disease can quickly mutate into a high-pathogenic form in commercial poultry flocks, he said.
"There is a vast and total difference between an H5 and an H7 subtype," Clark said in an interview.
The CFIA will investigate to see if it can find the cause of the infection, and will test birds within 10 kilometers of the farm, Clark said.
There is one other commercial poultry farm within that radius and several small backyard hobby flocks, Clark said.
Canada had its first major outbreak of bird flu in 2004 in British Columbia's densely populated Fraser Valley. About 16 million poultry were destroyed to limit the spread of the virus.
A smaller outbreak was also seen in British Columbia in 2005.