An exciting headline but bizarre happening. There is a devastating bird flu epidemic in Canada, of H7N3 one of the varieties which has struck the US in the past several years, among other places. However, USDA APHIS confused their response. Add this to the confused response (early 2006) and preparations we’ve had in Alaska and it makes one queasy.

The current highly pathogenic flu is specific to birds, primarily domestic birds. It can be lethal to domestic birds or otherwise make them too sick for market.

This form of the virus does have the potential to evolve or mutate into a form infectious to humans. This is a low probability. See the ProMed article below for more details.

U.S. border agents seize hunters’ birds amid Canada’s bird flu scare
http://canadianpress.google.com/article/ALeqM5h67G39MWQ33ZzdaJ-P9S0qKYsX_g
9 hours ago

ST. PAUL, Minn. – U.S. Customs officials in Minnesota and North Dakota seized more than 4,100 birds from hunters re-entering the United States from Canada following an outbreak of avian flu at a commercial chicken farm near Regina….

On Thursday, the U.S. Department of Agriculture’s Animal Plant Health Inspection Service banned all imports of poultry and unprocessed bird products and customs agents were told the ban included hunter-killed birds…. The confiscated birds were sent to landfills. Birds also were confiscated at border crossings in Montana and at Canadian airports.

Agriculture Department officials rescinded the order on hunter-killed birds late Saturday night after reviewing their protocols….

“Biologically, it makes no sense whatsoever,” said Michael Chamberlain, a professor at Louisiana State University. “They were saying you can’t transport a hunter-killed bird across the border, when millions of birds are migrating across the border already?”

While the Saskatchewan avian influenza is not the H5N1 virus that has caused worldwide alarm, USDA officials said the H7N3 virus is a considerable threat to commercial poultry farms. […]

ProMed The outbreak of H7N3 in Canada
Date: 27 Sep 2007 Source: Canadian Food Inspection Agency [edited] http://www.inspection.gc.ca/english/corpaffr/newcom/2007/20070927e.shtml

Avian influenza detected in Saskatchewan

Highly pathogenic H7N3 avian influenza has been detected in a commercial poultry operation in Saskatchewan, the Canadian Food Inspection Agency (CFIA) announced today [27 Sep 2007]. 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….

Once all birds have been removed, the CFIA will oversee the cleaning and disinfection of the barns, vehicles, equipment and tools to eliminate any infectious material that may remain.

To limit any potential virus spread, the CFIA will apply restrictions on the movement of poultry and poultry products within three kilometres [1.86 miles] of the infected premises. As an additional safeguard, any poultry operations within ten kilometres [6.2 miles] of the infected premises will be closely and regularly monitored for signs of illness….

The CFIA’s actions are consistent with internationally recognized animal health guidelines and the CFIA’s established avian influenza response protocols.

It may be difficult to identify the source of the virus, but the possibility of exposure to wild waterfowl — which are the natural hosts for the virus — cannot be discounted. Poultry owners are urged to take an active role in protecting their flocks by keeping them away from wild birds and areas frequented by wild birds….

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Communicated by:
[2] Date: 29 Sep 2007 From: Dr. Emily Jenkins and Dr. Catherine Soos [The following post is in reference to ProMED-mail post 20070928.3210 – Mod.TG]

The current outbreak in Saskatchewan poultry has been linked to a highly pathogenic strain of H7N3 avian influenza ( http://www.inspection.gc.ca/english/corpaffr/newcom/2007/20070927e.shtml).

The H7N3 strain of avian influenza is a potential zoonosis with low risk of transmission, causing mild conjunctivitis in 2 heavily exposed people in the 2004 outbreak of highly pathogenic H7N3 in the Fraser Valley, British Columbia, Canada. The concern, of course, is that people co-infected with avian and human influenza viruses could serve as mixing vessels for viral recombination and subsequent development of human adapted, virulent strains of influenza.

Wild birds are frequently implicated in outbreaks of avian influenza in poultry, often with little or no supporting evidence (Please reference ProMED-mail post 20051124.3409).

Highly pathogenic strains are not commonly carried in migratory waterfowl; indeed the recent highly pathogenic H5N1 outbreak in Eurasia is an anomaly in that wild birds may be acting as carriers and victims of a highly pathogenic strain of avian influenza. Wild birds are the natural hosts of low pathogenicity strains, which can mutate into high pathogenicity strains in intensively managed poultry. As such, enhanced biosecurity to prevent bidirectional spillover between wild and domestic birds is well warranted, but speculation about the source of the virus in this outbreak is premature pending epidemiological and molecular characterization.

Investigation into the source of the virus will be facilitated by recent surveillance for avian influenza in 1000 wild ducks in southern Saskatchewan in August 2007, which occurred as a part of Canada’s Interagency Wild Bird Influenza Survey, in collaboration with the United States Department of Agriculture to enhance surveillance in the Central Flyway. Results from 2007 are pending.

In 2006, no H5 or H7 strains were detected in samples from 56 ducks (primarily northern pintails) in southern Saskatchewan, although there were 6 positives for non H5/H7, low pathogenicity influenza A viruses (based on PCR). Canada-wide, no H7 subtypes or highly pathogenic strains were detected in 4268 samples from wild ducks in 2005, nor in over 12,000 samples from wild birds in Canada in 2006: http://wildlife1.usask.ca/en/aiv/index.php

At the moment, there appears to be no scientific justification for increased concern over the avian influenza status of hunter-killed wild birds in Saskatchewan, including export to the USA. Resident and non-resident hunting of wild waterfowl is a major activity in Saskatchewan at this time of year. As usual, hunters should observe common sense food safety and handling precautions: http://www.phac-aspc.gc.ca/influenza/fs-hwb-fr-mos_e.html

ProMED-mail is a program of the International Society for Infectious Diseases. Read the previous reports here.
http://www.isid.org


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