The Canadian Food Inspection Agency (CFIA) reports seven commercial poultry locations in Southwestern Ontario have been affected by a highly contagious avian influenza since Dec. 14. Worry about bird flu has been ramping up because of a B.C. teen's recent case and the spread of the virus to dairy herds in the United States.
WHAT IS BIRD FLU?
Avian influenza reported in Southwestern Ontario are variations of the H5N1 bird flu that has been persisting in wild birds internationally for more than two years, said Scott Weese, an infectious diseases veterinarian and professor at Ontario Veterinary College at the University of Guelph.
Weese said the virus is circulating “in wild birds fairly effectively and that means spillover risk of infection into domestic animals” such as poultry and mammals, “especially mammals that will catch and eat birds.”
WHERE HAS BIRD FLU BEEN REPORTED IN THE LONDON REGION?
The Canadian Food Inspection Agency reports seven outbreaks of the highly contagious H5N1 bird flu in Ontario, all of them in the London region.
The agency maintains a robust website tracking the presence of bird flu in Canada.
Four of the sites with confirmed outbreaks of H5N1 bird flu are in Oxford County, two are in Strathroy and a seventh in North Middlesex was added to the agency’s list of infected premises in the province on Friday afternoon. More than one million birds have been impacted. The first outbreak occurred Dec. 14 on a Strathroy farm.
There are 69 other active infected premises country-wide, although two in Quebec are reported to be a low pathogenic avian influenza strain, the agency says. All but six of the active cases are in British Columbia.
WHO IS AT RISK FROM BIRD FLU?
The virus poses “multiple levels of concern,” Weese said, such as the virus’s potential to “jump between species and adapt.
“It doesn’t spread very well person to person, or spread at all person to person,” Weese said of the virus, but warned it could be problematic if that changed, especially into a transmissible infection that humans haven’t encountered previously.
“If it changes and mixes to be something that's adapted to spreading human to human, then it could be incredibly severe, an incredibly big problem,” Weese said.
He said the number of people infected by H5N1 is “relatively small” but noted a recent case in British Columbia where a teen became very ill.
Canadian health officials said this week the teen has been taken off of supplemental oxygen and is no longer infectious.
There is also the risk to poultry, which Grant Loney of the Canadian Food Inspection Agency said, “Definitely can be lethal.”
“Unfortunately, for poultry, it can be devastating,” he said. “It's often birds are sick, lethargic, very soon after exposure to the virus, and they'll start showing signs and dying.”
Loney said that due to the virus’s proliferation, many birds are slaughtered to prevent the further spread of infection, which can be costly to farmers.
“This strain has significant impacts on poultry, so there are big issues there, from a farming standpoint,” Weese noted, adding disruptions can potentially cause food costs to rise as a result of millions of birds affected by the contagious infection.
“Since December 2021, the avian influenza outbreak, has resulted in more than 11 million domestic birds being destroyed in nine provinces,” Loney said.
HOW DOES BIRD FLU SPREAD?
Both Loney and Weese described migratory birds as the primary factor in the virus’ widespread transmission.
Weese provided an example of the common cold circulating when children return to school in September when they’re “mixing” and “another boom” around Christmas.
“Migratory birds cause more problems because they move more and you get that daycare effect during the migration season, where you get lots of different birds from lots of different areas, mixing along flyways,” Weese said.
Loney said interactions with wild birds, often near ponds or rivers or streams close to farms can result in the infection’s spread.