'Unprecedented' virulent avian influenza wave appears to be fading in Alberta

The wave of highly pathogenic avian influenza that caused unusually severe illness in wild birds and lead to the deaths of roughly 950,000 domestic poultry in Alberta appears to have eased.

It has now been more than a month since the last farm flock reported the disease.

"I think our numbers are going down," says Dayna Goldsmith, a veterinary disease pathologist with University of Calgary's faculty of veterinary medicine and Alberta director for the Canadian Wildlife Health Cooperative.

The falling number of reported dead wild birds is expected as migratory ducks and geese make their way past Alberta and on to their summer nesting grounds in the north. The 2022 outbreak has still hit wild flocks in unusual ways.

"We haven't seen this before, it is unprecedented, at least in terms of since we've been recording it, this outbreak is really unusual for a variety of reasons," Goldsmith says.

Avian influenza is always circulating in wild populations, Goldsmith says, but generally only causes low level illness.

This year, birds appeared to be much sicker, some having trouble holding their necks up, exhibiting head tremors or moving in circles.

"It's high path and its killing them, so its unusual for that reason, but its also unusual for how wide spread it is -- it's across several countries," says Goldsmith.

The current strain also shows an ability to infect other species more readily, including eagles and hawks, as well as mammals such as skunks. It's also turning up in corvids -- a family of birds which include crows, magpies and ravens.

"We are of course worried about whether we will see something similar in the fall migration, it really depends on how many birds got exposed this time around and are immune versus how many are still naive," she said.

Domestic chickens, turkeys and ducks are particularly "naïve," they lack almost any immunity to avian influenza, which has lead to the widespread "depopulation" of farms around the world.

Alberta has been the hardest hit in Canada. A total of 31 flock infections have been recorded, leading to the deaths of roughly 950,000 birds.

The next most affected province has been Ontario with 26 flock infections killing 560,000 birds.

"We're making pretty good progress on achieving those milestones of cleaning and disinfection. And so you'll start to see those numbers drop here over the next couple of weeks for sure,” said Noel Ritson-Bennet with the Canadian Food Inspection Agency, which is in charge of euthanizing birds and disinfecting affected farms.

Just two of Alberta's 31 affected farms have been cleared to resume normal operation. Already eyes are on the fall migration when infected wild birds will almost certainly return.

"There's every possibility that they'll bring the virus with them again. It's hard to say at this point in time, what that will mean in terms of whether there's an increased risk," said Ritson-Bennett.

Goldsmith says while the disease may have settled down by fall with fewer acute cases, chicken farmers will need to stay focused.

"They have to be really good about their biosecurity and keep the infection out because you can't let it into the population or we'll be in trouble," Goldsmith says.

Avian influenza is a reportable disease, which means domestic bird owners must report cases to the CFIA. While it can infect humans, the current strain does not appear to cause serious illness.

If you find a bird you suspect has died or is dying of avian influenza, don't handle it. If for some reason you feel you must handle it, wear protective gloves and preferably a mask.

You can also call the province at 310-0000 to report.