As the avian influenza continues to spread in Canada, even infecting mammals, an expert says the risk of transmission to humans and pets is low but health officials must remain on high alert.
Health officials announced earlier this week a pet dog in Oshawa, Ont., had died after testing positive for H5N1, the virus that causes the bird flu. The Canadian Food Inspection Agency and the Public Health Agency of Canada said the dog developed symptoms after chewing on a wild goose.
But Dr. Shayan Sharif, professor and acting dean of the University of Guelph’s Ontario Veterinary College, says at the moment, the risk for pets remains “very low.”
“What could be the risk in the future? I think if the virus begins mutations and adapting itself further to mammals, then things could be different,” he said in an interview on Wednesday with CTVNews.ca. “At the moment, I would say it’s very low transmission risk.”
It was the first and only case so far of a pet dog contracting bird flu in Canada, which is also a rare occurrence worldwide. A case of a dog contracting bird flu was reported in Thailand all the way back in 2004 and described in a 2006 case report. A 2008 study in Germany and Austria also found that the H5N1 virus was present in 1.8 per cent of a population of 171 cats.
“It has happened that the virus has transmitted from birds to dogs and cats and there’s good evidence that dogs and cats could become infected, but not frequently. It’s only rarely they’re becoming infected,” Sharif said.
The avian flu has also infected other mammals. Last month, several skunks in the Vancouver area were found dead after testing positive for the virus. Bird flu has also been discovered in foxes, seals, dolphins, black bears, mink, raccoon and porpoises across Canada.
Sharif notes that the H5N1 is well adapted to avian species, but not so well adapted to mammals, which makes it difficult for transmission between mammals to occur.
“When (bird flu) jumps from avian to mammals, those mammals usually become the so-called ‘terminal hosts,’ meaning that they can’t try transmit the virus to other mammals. And there’s no evidence at the moment that, for example, dogs can transmit the virus to other dogs or transmit the virus to their owners, to humans,” he explained.
However, if the virus mutates to be better adapted to mammals, Sharif says that’s “one step closer to gaining the capacity for mammal-to-mammal transmission.”
“That’s precisely what we are hoping it would never be able to do.”
Since 2022, the avian influenza has wreaked havoc on the poultry industry, affecting 7.2 million birds in Canada as of March 29. Currently, 59 farms across Canada are dealing with outbreaks, while previous outbreaks have occurred at 245 farms.
Canadian health officials are urging pet owners to not feed their pets any raw meat from game birds or poultry and never let their pets consume or play with dead wild birds found outside.