Increase in bird flu cases sounds alarm bell

Canadian government experts are warning that a rise in bird flu cases and rapid spread among livestock and wildlife could also pose a threat to humans.

The Canadian Food Inspection Agency (CFIA) says the H5N1 subtype of influenza spreads rapidly among poultry farms, but wild birds are disproportionately affected by the virus due to a lack of surveillance.

The agency’s website shows that as of Nov. 2, approximately 7.9 million poultry were infected with the disease.

That total does not include the approximately 2,500 wild birds that have tested positive or suspected positive for avian influenza, according to the Canadian Wildlife Health Cooperative.

Experts say influenza is deadly to poultry not because of the virus itself, but because of influenza policies in chicken houses.

When poultry becomes infected with a highly contagious subtype of avian influenza, all birds that have come into contact with the animal are euthanized to prevent further spread, according to the CFIA website.

But in the case of wild birds, spread is not so tightly controlled. The virus often spreads unchecked, and some experts warn it has mutated to infect other species.

“The more a virus spreads, the more it evolves and changes,” explains Jennifer Provencher, a research scientist with Ecotoxicology and Wildlife Health at Environment and Climate Change Canada.

“This particular H5N1 virus is different from viruses we’ve encountered before, and it’s causing very widespread death,” he told CTVNews.

“Just like humans, when birds congregate on the landscape during migration, they transmit it to each other. “When they enter nesting areas, they disperse throughout the landscape and transmission stops,” He said.

Bird flu was first discovered in Canada in 2004 and has a history of mutating into subtypes that can easily infect humans.

Currently, human cases of H5N1 infection are extremely rare; more than 800 people worldwide have been infected with the virus since 1997, according to Health Canada.

H5N1 doesn’t just infect birds, however: cases have been found in foxes, cats, dogs and other mammals.