After a dog in Ontario recently contracted avian flu and died, experts say pet owners should be more vigilant — even though the risk of transmission to mammals remains low.
The infection strain, called H5N1, also known as bird flu, is a highly pathogenic form of avian influenza virus A and circulates most easily between birds. Although it’s rare for it to spread to mammals, numbers are increasing across Canada.
The dog from Oshawa, Ont., was infected with the bird flu after chewing on a wild goose, and then developing “clinical signs,” the Canadian Food Inspection Agency (CFIA) said Tuesday. The case was confirmed on April 1 and the necropsy, which showed the respiratory system was involved in the death, was completed on April 3.
Although the CFIA said the risk of humans and domestic pets contracting the virus remains low, Scott Weese, a veterinary internal medicine specialist and professor at the University of Guelph’s Ontario Veterinary College, said pet owners should still exercise caution as the risk is not zero.
“This dog could have easily been missed because if they hadn’t noticed the encounter with the bird, that wouldn’t have triggered any testing,” he said. “So is this the only dog that’s been infected in Canada, or is it the only dog we’ve diagnosed? It’s hard to say.”
Overall, domestic pets getting infected with the bird flu is rare, but the problem occurs when “you have a lot of background noise going on,” he explained.
“If it’s a rare, one-in-a-million chance, but you get millions and millions of birds, that one-in-a-million chance starts to get more common.”
The World Health Organization (WHO) has called the ongoing circulation among poultry concerning. During a WHO media conference on Thursday, Dr. Maria Van Kerkhove, an infectious disease epidemiologist, said the transmission from poultry to mammals is “always of concern.”
“As a pathogen that has that zoonotic risk, that spillover risk, the concern is if it has that amplification aspect,” she said. ” It is something the organization takes very seriously as pathogens that have epidemic and pandemic potential.”
Hunting dogs may be more at risk
Transmission between mammals usually happens when an animal eats or chews on a bird, Levon Abrahamyan, a virologist at the University of Montreal, said.
“These cases are very rare, and they happen when there is very direct contact with a large number of viral particles,” he said. “And this can happen with a dog or any animal, including a human, is in close contact with a high concentration of the virus.”
This is why the bird flu has been transferred more to the “opportunistic carnivores,” like foxes, raccoons, skunks, wild cats and ferrets, Abrahamyan said.
For example, last month eight skunks that were found dead in the Vancouver area tested positive for the H5N1 avian influenza. B.C. health officials said the skunks may have contracted the virus by eating infected wild birds.
In terms of domestic animals getting infected, Abrahamyan believes hunting dogs are most at risk.
Duck hunting in Canada is typically in the fall, but if the bird flu continues to spread across the country, the virus could still be present in September and October.
“In the case of domestic dogs, it’s very rare the dog could get it. But a dog that can be at higher risk is the hunting dog,” Abrahamyan warned. “I would highly recommend for hunters to take precautions now that we have a highly pathogenic influenza among wild birds.
“They should watch their dogs as a dead bird has a higher possibility of having the virus, as you don’t know what caused the death.”
How to protect your pet from bird flu
The avian flu affects all types of birds, like ducks, swans and geese. It especially affects those that tend to stay in flocks or congregate together. The virus is transmitted from bird to bird through secretions, feces and contaminated feed, water and equipment, according to the Canadian Centre for Occupational Health and Safety.
It can also be fatal, so when scavenger animals like skunks (or even a dog) eat an infected bird, they can also get the virus.
“We don’t want dogs roaming around where they have a close encounter with, say, a goose, as geese tend to stand their ground,” Weese said. “Your dog goes up and barks at it and the goose will bark back. And that’s that close contact that we want to prevent.”
If there is a park that dog owners enjoy, but it’s flooded with geese this time of year, Weese said it’s probably not a great place to take your pet, as the goal is to “reduce that bridge between wildlife and domestic animals.”
Weese said he has two dogs of his own and lives in rural Ontario, so there are ducks and geese all over the place.
“I’m not being overly restrictive with my dogs, but I’m not going to let them go chase geese in the pond. If there’s a dead bird, I’m certainly going to keep them away and I going be more restrictive. But I’m not going to keep them completely on leash in areas where I know that we don’t see a lot of birds.”
In terms of feeding pets raw meat, Weese said if a dog is on a raw meat diet, there shouldn’t be a risk of avian flu because it’s the same as buying poultry from the grocery store.
“There’s no risk of influenza there,” he explained. “Poultry is really, really well monitored. They’re not going into the food chain if they’re infected.”
But he warned that dog owners should not hunt their own birds to feed their dog, or have their own backyard poultry, as these are “big amplifying” sources for the virus.
Are there risks with birdfeeders and avian flu?
As cases of avian flu steadily rise in Canada, Weese said birdfeeders can pose a risk, especially for “birds themselves, as feeders are co-mingling sites.”
“You’re bringing together birds that might not be getting close together otherwise. And you’re also creating more of that risk of the bird’s secretions and bird poop that’s on the feeder. So it might be a place where you’re going to amplify the virus if one of them has it,” he said.
There also is the danger of the bird feeder bringing in more animals that are close to the human and pet population.
He recommends keeping cats indoors if possible but acknowledges that may be difficult to do in some situations.
“If you have an outdoor cat in particular, it’s probably not good to have a feeder as it creates a greater chance for that cat to catch a bird and then the cat is more likely to catch a sick bird,” Weese added.
If people do want to keep their feeder or bird bath around this spring and summer, Abrahamyan recommends washing it frequently with a mixture of vinegar and soap, in order to maintain a clean environment.
“You don’t want your bird feeder or bath to become a source of the transmission of this virus, so regularly clean it and it should be fine,” he said.
In December 2022, the British Columbia Society for the Prevention of Cruelty to Animals (BC SPCA) urged residents to take down their bird feeders, warning it puts birds — including great horned owls, bald eagles, great blue herons, ducks and geese, and crows — at risk of the virus.
The BC SPCA called on people to remove seed and suet bird feeders, in order to discourage birds from gathering and potentially spreading the disease.
These feeders create “unnatural congregations” of birds who can pass the virus to one another, or contract it from other bird droppings on the ground underneath the feeder as they forage for fallen seed, the organization stated.
— with files from Global News’ Simon Little