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Cause For Concern

The last thing this province’s struggling hog sector needed was a global pandemic named after swine.

Although the origins of the disease outbreak in Mexico have not at this time been traced back to pigs, the paranoia that has grown as it spreads human to human across the globe has been disastrous for the pork sector. At last count, 20 countries have stopped trading in pork, Egypt embarked on a mass cull of hogs and market prices have tanked – once again.

It’s a bad rap that has left producers justifiably upset and resentful.

The myth that the disease comes from swine has been damaging enough. But the reality that humans carrying this virus can make the hogs sick is an even bigger threat.

That was amply demonstrated over the weekend when it was disclosed that an Alberta carpenter who had recently travelled to Mexico infected a swine herd, even though he was working on the barn and did not come into direct contact with the pigs. It was not known as of press time how widespread the trade implications of this might become.

But it underscores a pressing need for a review of biosecurity protocols in light of some inescapable facts:

Manitoba raises a lot of hogs. Those pigs travel. So do people. And finally, the risk of zoonotic infections with pandemic potential is rising for a host of reasons, including all of the above.

Veterinary and medical health officials have rightly called for increased vigilance on the part of hog farmers and rural veterinarians. Although federal officials have said they won’t restrict the agricultural sector’s access to foreign workers at this time, those workers will be required to go through additional medical screening.

Dr. Chris Olsen, a researcher with the School of Veterinary Medicine at the University of Wisconsin, Madison stressed in an interview last week that it is important for producers to heed the warnings.

In 2005, Olsen was involved with a study based in Canada that first identified the potential for swine to act as a vector for new strains of influenza based on human, swine and avian viruses.

Collaborative efforts between medical and veterinary researchers determined that an Ontario farm worker who developed flu-like symptoms shortly after the pigs in the barn where he worked had developed influenza suffered from the same H3N2 Influenza A.

It was well known that humans and swine can exchange flu viruses, but this was the first known case of illness caused by a human, classical swine and avian influenza reassortant. The fact that both avian and human flus can infect pigs makes them capable of being the vessel for influenzas to develop multi-species potential. The H1N1 making the rounds now also contains genetics from human, swine and avian influenza.

Olsen said researchers have been noticing increased evolutions in the dominant swine flu strains in North America since the late 1990s, after nearly 60 years of relative stability. However, he noted the increase could also be partly related to improvements in the tools used to monitor the viruses.

Before 1998, the swine flu in North America was almost solely related to H1N1 virus.

Manitoba has already had experience with these new influenza types. In early 2005, the virus was identified in Canadian hog and turkey barns for the first time. It spread rapidly – first surfacing in Manitoba, and moving to Alberta, British Columbia and arriving in Ontario in July.

Researchers also found the extent of crossover between humans and hogs was higher than expected. In one study of 74 swine farm owners, employees and their family, 23 per cent tested positive for H1N1 viruses.

Most hog barns in Manitoba already practise strict biosecurity. The shower-in, shower-out rules and keeping facilities off limits to outsiders are well known. But a shower and a change of clothes won’t address the problem of virus hitching a ride into a barn in a worker’s nasal passages, which is what appears to have happened in the Alberta case.

And the rules are only as good as their enforcement. According to the Manitoba Pork Council, at least one Manitoba producer courted disaster last week by allowing a television crew into his facility.

It’s a dilemma. The media has an important job to do. Meanwhile industry participants want their story to be told. Biosecurity enforcement is easily misinterpreted as secretive and unco-operative.

The industry could help to partially address this by supplying stock footage captured under sterile conditions to help reporters tell their story. Reporters can also be directed to the National Centre for Agriculture and Environment which allows visitors to view conventional and alternative hog production systems through windows.

The Manitoba hog industry will be lucky if a temporary price downturn is the only fallout from this flu outbreak. It needs to take steps now to prepare for the next one. [email protected]

About the author

Vice-President of Content

Laura Rance

Laura Rance is vice-president of content for Glacier FarmMedia. She can be reached at [email protected]



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