New strain of bird flu spreading in Canada: Can it infect humans?

A strain of bird flu is adapting to infect mammals, raising concerns it could eventually jump to the human population — and one veterinarian says there's potential it could drive another pandemic.

The infection strain, called H5N1, is known as a "highly pathogenic" form of avian influenza virus A and it spreads most easily between birds. Current known human infections have only been the result of direct contact with infected birds, according to a report by the D.C.-based think tank Institute for Progress.

"It's already infected birds across Canada, all provinces in Canada have reported cases of this particular strain of bird flu," said Dr. Shayan Sharif, a professor at the University of Guelph and the Associate Dean of the school’s Ontario Veterinary College.

In an interview with CTV's Your Morning Wednesday, Sharif said there is concern as it seems the virus is becoming more adapted to infecting mammals.

"It means that it’s probably just a few mutations away from containing the capacity for transmission. We can’t really say this with a significant amount of confidence at this moment, but there are various different pieces of the puzzle that seem to be coming togethe" he said.

According to data compiled by the Canadian Food Inspection Agency along with Climate Change and Environment Canada and the Canadian Wildlife Health Cooperative, there are 1,730 confirmed and suspected cases of bird flu overall in Canada as of Feb. 15. The majority of cases are in Quebec (359), Alberta (268) and Saskatchewan (246).

Currently, there is an ongoing quarantine of multiple farms in Fraser Valley, B.C. due to H5N1. In Quebec, thousands of sick birds were culled in summer 2022.

In Canada, the Canadian Food Inspection Agency responds to outbreaks by engaging in the "humane destruction" of infected and exposed animals, surveilling and tracking, implementing quarantine and animal movement controls, decontamination practices and zoning to indicate infected and disease-free areas.

An outbreak in farmed minks in Spain in October raised concerns the virus is jumping to mammals. Researchers reporting on the incident emphasized the need for increased biosafety and biosecurity measures in the farming system,and surveillance programs are needed at a global level.

According to the World Health Organization, since 2003 there have been 240 recorded cases of bird flu in humans, of which 135 were fatal.

But Sharif said the likelihood of the disease spreading among humans is low because,while the illness has jumped from animal to humans, those people have become "terminal hosts" who were unable to transmit it to others.

"If the virus remains as such then there’s a significantly low likelihood of this virus being able to transmit from humans to humans, but there’s always a chance," he said.

For more information, watch the interview above with Sharif.