The virus, of the H5 subtype, has been found on one farm in an area densely populated with poultry operations. The other farms have been quarantined because of their proximity to the affected farm, officials said Tuesday.
"The quarantines that have been put in place are intended to be proactive measures to assure containment and minimization of the potential for spread of the disease," said Paul Mayers, vice-president for policy and programs for the Canadian Food Inspection Agency.
Mayers said additional farms may be added to the quarantine list in the coming days.
The National Centre for Foreign Animal Diseases in Winnipeg is conducting testing to determine the neuraminidase — the N in a flu virus's name — subtype of the virus.
They will want to see if the culprit is an H5N2 virus that has been hopscotching among poultry operations in British Columbia and a number of U.S. states since late last year.
In addition to B.C.'s Fraser Valley — where an outbreak that started last December appears to be under control — this virus has been found in Washington, Oregon, Idaho, Minnesota, South Dakota, Montana, Kansas, Arizona and Missouri.
The lab is also testing to see if the virus is highly pathogenic or of low pathogenicity. But given its behaviour so far, that seems to be almost a forgone conclusion.
The outbreak was discovered when turkeys on the affected farm starting to die last Friday. To date approximately 7,500 birds have died, said Dr. Greg Douglas, Ontario's chief veterinarian. That is out of a flock of 12,000.
Low path bird flu viruses can diminish egg production but they do not typically kill poultry. Douglas said the remaining birds on that farm will be euthanized humanely.
The affected birds will not be put into the food chain. But officials say properly cooked poultry does not pose an infection risk to people.
Occasionally humans have been infected with some H5 viruses, particularly an H5N1 virus that has been circulating in Asia and the Middle East since 2003. But so far this H5N2 virus has not been seen to have infected people.
H5 viruses are among two subtypes of bird flu that have the capacity to become highly pathogenic, which means they pose substantial risks to commercial poultry operations. The other subtype is H7.
As a consequence, international trade rules allow countries to levy sanctions when outbreaks caused by H5 or H7 viruses are discovered. Even low path versions of these viruses would be expected to trigger trade sanctions, because the viruses will generally ratchet up in virulence as they circulate among birds.
Japan and Taiwan have already barred poultry from Ontario in response to this outbreak, Mayers said. Meanwhile, 10 countries continue to ban poultry from Canada because of the H5N2 outbreak that hit British Columbia.
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