TORONTO – A highly contagious strain of bird flu is spreading across North American farms and killing millions of chickens, but experts say the risk of human transmission remains low.
Since late last year, the Canadian Food Inspection Agency (CFIA) has identified outbreaks of the H5N1 strain of avian influenza in at least 20 commercial and backyard poultry flocks in Ontario, Alberta, Nova Scotia and Newfoundland and Labrador.
Many farms have been kept in quarantine. In southwestern Ontario, the CFIA established two avian containment zones to prevent the spread of bird flu.
In the United States, the Centers for Disease Control and Prevention says that poultry outbreaks have been reported in 24 states, killing about 23 million chickens and turkeys.
However, the origin of this recent wave of outbreaks is unclear.
“It’s a multimillion-dollar question,” Dr. Shayan Sharif, a professor and associate dean at Ontario Veterinary College, said Thursday in a phone interview with CTVNews.ca. “What we do know is that it originated in eastern Canada.”
Avian influenza occurs naturally in many wild birds, which can then be spread to poultry farms through bird droppings and nasal secretions. Experts say vehicles carrying contaminated equipment, clothing, footwear and supplies can also spread the flu within poultry farms.
The first cases of bird flu were confirmed at a farm in Newfoundland’s Avalon Peninsula last December, following the sudden death of birds over a period of several days. A second outbreak was confirmed in the Avalon Peninsula in January.
By February, flu had spread to farms in Nova Scotia and the US, and between March 27 and April 6, bird flu was reported in 10 flocks in Ontario.
This time of year is one of the busiest seasons for migratory birds. Sharif believes the flu is likely to spread to more provinces. While no outbreaks have been recorded on farms in Quebec, three cases of avian flu have been detected in Canadian geese in the province.
“Migratory birds, their flight paths are very clear. But sometimes, they can wander off to other places. So, as a result, I wouldn’t be surprised to see if other provinces are being affected as well, but There is no hope,” he said.
While no outbreaks have yet occurred in zoos, organizations such as the Toronto Zoo are closing aviaries to the public and adding extra security to bird enclosures to keep wild birds out.
Less risk to humans: Experts
Fears of a Canadian bird flu outbreak have prompted some countries to impose trade restrictions on Canadian poultry products.
South Korea and the Philippines have banned poultry products from across Canada, while the US and Europe are restricting products from specific regions that have seen outbreaks.
But Sharif says it is “highly unlikely” that any human will contract the virus from food.
“Even if it is in human food, the reality is that this virus is susceptible to heating. Therefore, cooking your chicken or cooking your eggs will completely eliminate the virus.
Ontario’s Ministry of Agriculture, Food and Rural Affairs also stated that bird flu “does not pose a threat to food security” and that the province’s poultry and eggs are “safe to eat when properly handled and cooked.”
So far, there have been no cases of bird flu infecting humans in Canada or the US, but Sharif says he is still concerned about the potential for avian influenza viruses to infect humans, noting that This virus has a high ability to mutate.
“I’m watching this very carefully because this virus, like all influenza viruses, has a wide range of host species,” he said. “If it mutates, and if it acquires the potential for transmission in humans … you could be dealing with another pandemic virus.”
With files from The Associated Press and The Canadian Press.
