Canada clamps down quickly on H7N3

A new case of low pathogenic avian influenza in North America.

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It was only low pathogenic avian influenza (LPAI) of the strain H7N3 but the Canadian authorities moved quickly all the same, following confirmation of the Saskatchewan outbreak on 27 September 2007. The infected farm is about 40km north of Regina in a region with relatively few poultry, but the Canadian Food Inspection Agency (CFIA) wasted no time in arranging for a mass cull of 50,000 chickens. They were clearly mindful of the time H7N3 LPAI struck Canada in 2004 mutating during the Fraser Valley (B.C) outbreak into a highly pathogenic form, and leading to loss of some 17 million birds and 1700 jobs in the $350 million poultry industry of British Columbia (B.C.).

“We are not dealing with the H5N1 virus that has been linked to human health,” Dr Sandra Stephens of the food inspection agency told Reuters. Dr Stephens went on to claim that H7N3 is not normally associated with serious illness but like other H7 sub-types, it has the potential to produce mild human illness. This is exactly what happened in previous H7N3 outbreaks in Canada and elsewhere when a few poultry workers suffered infections causing inflammation of the eyes and conjunctivitis.

With this in mind, CIFA were clearly taking no chances and gave flu vaccinations and the anti-viral drug, Tamiflu, to five workers who had been in contact with the birds on the farm. CFIA workers will be offered the same treatment, said Shauna Hudson, a medical health officer with Saskatchewan Health.

Lisa Bishop-Spencer of the Chicken Farmers of Canada was circumspect, claiming they were alert but not alarmed. The industry had developed protocols to deal with the disease anticipating its return, she said. There was no immediate fear of the virus getting into the food chain because the infected farm is a broiler breeder operation.

Dr Stephens (CIFA) said the outbreak would surely lead to restrictions on Canadian exports. The US moved quickly to ban poultry exports from Saskatchewan but this was largely symbolic since no poultry live or otherwise has been imported from Saskatchewan since 2005.

Japan’s predictable ban just 24 hours after the outbreak was confirmed is somewhat more serious. Last year, Japan imported more than 60,000 live chicks and 170 tonnes of poultrymeat from Canada, although the latter was just a fraction of the 300,000+ tonnes imported by Japan from all sources.

Agriculture Canada says total poultry and egg exports are from Canada are valued at around $325 million a year – just 7.5% of the one million tonnes of chicken produced each year across the country. Errol Halkai of the Canadian Broiler Hatching Egg Marketing Agency said that export of fertilised eggs was virtually non-existent.

Total poultry production in Canada is worth a whopping $2.4 billion a year but producers and the industry at large is banking on the fact that the outbreak is so far limited to one relatively isolated farm in a locality and region with a very low poultry population. A 3km zone has been established around the affected farm and any poultry operation within 10km is being closely monitored. In fact, there is only one other poultry unit within 10km this boundary and so authorities should be able to stamp out the disease quickly.

Nevertheless, Dr Stephens emphasised that CFIA is treating and handling the outbreak in accordance with international standards. All 50,000 birds were culled using carbon dioxide gas. Carcasses were either composted or buried deep in the ground. All barns, tools, vehicles and equipment were disinfected and the farm expected to remain under quarantine for 21 days.

It is impossible to pinpoint source of the outbreak say the authorities. The virus may have been carried into poultry houses on clothes or equipment or even a wild bird. Wild waterfowl including ducks and geese are known to carry the virus in North America.
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