As migratory birds — natural carriers of the bird flu virus — fly south, more cases are expected. And two recently reported outbreaks on Alberta farms put already struggling poultry producers at risk.
“We’re all a little nervous about this fall migration,” said Jeff Notenbomer, who owns Willow Creek Poultry, a broiler operation near Lethbridge.
While there is hope that operators are better prepared to prevent contamination, farmers are left wondering where and when the next outbreak will occur, Notenbomer said.
New cases and the return of birds such as wild geese have renewed concern about the spread, he said.
“We didn’t know what we were going to see in the fall, and now we’re starting to see the beginnings of something,” said Notenbomer, who is also president of the Alberta Hatching Egg Producers, which regulates broiler hatching production in the province.
“It’s a concern.”
Migratory birds are believed to be responsible for a number of outbreaks, a highly pathogenic strain of H5N1 bird flu now responsible for the deaths of more than 2.3 million cases in Canadian flocks and a number of outbreaks around the world.
Cases decreased this summer, following the spring migration period, but this year’s global outbreak has already taken a toll on Alberta herds. The province has been hardest hit in Canada.
Avian influenza is a notifiable disease in Canada. Federal inspectors respond to outbreaks by establishing quarantine 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 from the virus and others that have been euthanized.
Cases have been identified in a total of 37 operations since Alberta’s first case was confirmed in Mountain View County on April 6. There are 18 active cases. (Ben Nelms/CBC)
Outbreaks have been reported in a total of 37 practices since Alberta’s first case was confirmed in Mountain View County on April 6. As of Wednesday, there were 18 active cases.
The latest cases were reported Tuesday on farms in Starland County and Willow Creek Township.
The disease can spread to birds through contact with infected poultry and poultry products.
The virus can be spread on contaminated clothing, equipment, and even straw or shavings used as bedding in barns.
Health officials say that while bird flu can occasionally cause illness in humans, it is rare and would be the result of close contact with infected birds or highly contaminated environments, without eating contaminated meat from an infected animal.
With the Willow Creek outbreak about 20 kilometers from Notenbomer’s farm, he is reevaluating his biosecurity protocols and hoping to keep the infection out of his hatcheries.
Bird flu was first detected in Canada in 2004, but this year’s strain is different.
The new strain is highly contagious and appears to be persisting in wild birds — especially raptors, cormorants and waterfowl — while also killing them in unprecedented numbers.
(Canadian Food Inspection Service)
Margo Pybus, a wildlife disease specialist with Alberta Fish and Wildlife, said it’s important that farmers follow strict biosecurity protocols in the coming weeks.
The risk of transmission between wild and domestic birds will be high.
He also cautions that it is unclear which strain of virus the migratory birds will bring from their summer breeding grounds. Northern communities across Canada will be the first to know.
Alberta had a clearer picture of contamination risks during the spring, Pybus said.
The birds flying north over the United States provided conservation and industry officials with important clues about the transmission and severity of the new strain before this threat flew across the Alberta border.
“In the spring we were lucky because we could see what was happening at the southern end of the migration route,” he said.
“But for fall migration, it changes. And now we’re the first groups to see any of the Arctic migratory birds as they go further south, so we really don’t know what’s going to happen.”
Migratory birds, including geese, are carriers of the avian influenza virus and can transmit the infection to resident birds. (iStock/@arlutz73)
Wild birds flying south this fall will be carriers, but there is hope that the virus will have mutated and may prove to be less virulent and less deadly, Pybus said.
Just like COVID-19, the virus could become less severe as it spreads from host to host, he said.
“We’re certainly hoping it won’t be as deadly as the version of bird flu that was out there in the spring. But we won’t know until these birds actually start coming down in good numbers and we know whether our surveillance program is giving us reports of dead birds or not,” he said. “We’re all holding our breath.”
The province is testing wild birds for signs of infection, he said. No wild case has been identified since late July, but the province will continue to investigate bird deaths to identify any mutations.
Dr. Dayna Goldsmith, a veterinary pathologist at the University of Calgary, said the strain has proven to be highly unlikely, as cases have also been confirmed in mammals, including skunks and foxes.
He said the hope is that wild and domesticated birds exposed to the virus this spring will have improved immunity against the infection in the coming weeks.
“Controlling disease from a wildlife perspective is always very difficult, especially with something like this that is so easily transmitted and can infect so many different species,” he said.
“Unfortunately, we just have to let the population come to an equilibrium.”
