Chicken farmers brace for more cases of avian influenza as wild birds migrate

·5 min read
The Canadian Food Inspection Agency is investigating active outbreaks of avian flu in more than 50 flocks across Canada.  (David Mdzinarishvili/Reuters - image credit)
The Canadian Food Inspection Agency is investigating active outbreaks of avian flu in more than 50 flocks across Canada. (David Mdzinarishvili/Reuters - image credit)

Alberta chicken farmers are bracing for a second wave of avian flu infection this fall as the death toll among the province's flocks has surpassed one million.

As migratory birds — natural carriers of the avian influenza virus — fly south, more cases are expected. And two newly-declared oubreaks on Alberta farms are puting already-strained poultry producers on edge.

"We are all a little bit nervous about this fall migration," said Jeff Notenbomer, who owns Willow Creek Poultry, a broiler-breeding operation near Lethbridge.

While there is hope that operators are better prepared to prevent infection, farmers are wondering where and when the next outbreak will happen, Notenbomer said.

The new outbreaks and the return of birds like wild geese have renewed concern about the spread, he said.

"We did not know what we're going to see in the fall and now we're starting to see the start of something," said Notenbomer, who is also chair of Alberta Hatching Egg Producers, which regulates the production of broiler hatching in the province.

"It is a concern."

Migratory birds are believed responsible for a string of outbreaks a highly-pathogenic avian influenza strain of H5N1, that is now responsible for the deaths of more than 2.3 million cases in Canadian flocks and string of outbreaks around the world.

Cases waned this summer, following the spring migration period, but this year's global outbreak has already taken a toll on Alberta's flocks. The province has been the hardest hit in Canada.

Avian influenza is a reportable disease in Canada. Federal inspectors respond to outbreaks by establishing quarantines zones and ordering the destruction of all birds on site.

According to an update Wednesday from the Canadian Food Inspection Agency, an estimated 1,075,000 birds have been infected, 3,000 more than last week's update. The total includes birds that have died of the virus and others that have been euthanized.

Ben Nelms/CBC
Ben Nelms/CBC

Outbreaks have been declared at a total of 37 operations since Alberta's first case was confirmed in Mountain View County on April 6. As of Wednesday, there were 18 active outbreaks.

The latest outbreaks were declared Tuesday at farms in Starland County and the Municipal District of Willow Creek.

The disease can spread to birds through contact with infected poultry and poultry products.

The virus can spread on contaminated clothing, equipment, even the straw or shavings used as bedding in barns.

Health officials say that while avian influenza can occasionally cause illness in humans, it is rare and would be the result of close contract with infected birds or heavily contaminated environments, not eating infected meat from an infected animal.

With the Willow Creek outbreak around 20 kilometres from Notenbomer's farm, he's reassessing his biosecuirty protocols and hoping to keep infection out of his hatcheries.

Avian influenza was first detected in Canada in 2004 but this year's strain is different.

The new strain is highly transmissible, and appears to be sustaining itself within wild birds — particularly raptors, corvids and waterfowl species — while also killing them off in unprecendented numbers.

Canadian Food Inspection Agency
Canadian Food Inspection Agency

Margo Pybus, Alberta Fish and Wildlife's wildlife disease specialist, said it's important that farmers maintain strict biosecurity protocols in the weeks ahead.

The risk of transmission between wild and domestic birds will be high.

She also cautions that it is not clear what strain of virus migratory birds will bring back from their summer breeding grounds. Northern communities across Canada will be the first to find out.

Alberta had a clearer picture of the infection risks during the spring, Pybus said.

Birds flying north over the United States provided conservation and industry offfcials important clues about transmission and the severity of the new strain, before that risk flew into Alberta borders.

"In the spring, we were fortunate because we could see what was happening at the southern end of the migration route," she said.

"But for fall migration, it turns around. And now we're the first groups to to see any of the Arctic migrating birds as they go further south, so we really don't know what's going to happen."

iStock/@arlutz73
iStock/@arlutz73

Wild birds flying south this fall will be carriers but there is hope that the virus will have mutated, and may prove less virulent and less deadly, Pybus said.

Just like COVID-19, the virus could become less severe as it spreads from host to host, she said.

"We certainly hope that it won't be as deadly as the version of avian influenza that was there in the spring. But we won't know until those birds really start coming down in good numbers and finding out whether our surveillance program gives us reports of dead birds or not," she said. "We're all kind of holding our breath."

The province has been testing wild birds for signs of infection, she said. A wild case has not been detected since the end of July but the province will continue to investigate bird deaths to track any mutations.

Dr. Dayna Goldsmith, a veterinary anatomical pathologist at the University of Calgary, said the strain has proved incredibly unpredciable with cases also being confirmed in mammals, including skunks and foxes.

She said the hope is that wild and domesticated birds exposed to the virus this spring will have improved immunity against infection in coming weeks.

"Controlling disease on the wildlife side is always really difficult, especially with something like this that's so easily transmitted and can infect so many different species," she said.

"Unfortunately, we kind of just have to let the population come to an equilibrium."