An ongoing outbreak of a deadly strain of avian flu has already killed millions of birds, and it’s becoming even more of a concern as it spreads to mammalian species.
“This is an infection with epidemic and pandemic potential,” Dr. Isaac Bogoch, a Toronto-based infectious disease specialist, told the CBC. “I don’t know if people realize how important this is.”
The bird flu virus H5N1 is not brand new. But previously it mainly infected birds on poultry farms. However, in 2020, gene swapping between poultry and wild bird viruses created a “wild bird-adapted” version of the virus, according to the Centers for Disease Control and Prevention. This made it much easier for migrating wild birds to spread the virus to each other and domestic birds in their path.
A rooster is held in a cage on a farm in Austin, Texas on January 23, 2023. An avian flu strain is becoming a cause for concern as it crosses over into mammalian strains.
Since 2022, H5N1 has led to the deaths of more than 58 million domestic birds such as chickens, ducks and turkeys in the United States alone. When the deadly virus hits poultry or egg farms — some of which have more than a million birds on site — the facility usually kills the entire flock to prevent further spread.
In the same time span, there were nearly 6,000 cases in wild birds in the US
Scientists have also found several wild mammals infected with the virus, including bears, foxes, otters and seals. As of October 2021, there have been five confirmed human cases and one death worldwide, according to the BBC.
Ian Brown, the director of scientific services at Britain’s Animal and Plant Health Agency, told the BBC he was “very aware of the risks” of avian flu becoming a pandemic among humans.
“This global spread worries us,” he said. “We need to look globally at new strategies, those international partnerships, to tackle this disease. If we don’t solve the problem globally, we will continue to be at risk.”
A dead pelican, possibly infected with bird flu H5N1, is seen in Lima, Peru on December 7, 2022.
In October, a major outbreak occurred at a mink farm in Spain. Researchers who described the outbreak in a paper published last month believe wild birds initially transmitted H5N1 to mink farms, but once there, it spread from mink to mink.
“This outbreak signals the very real potential for the emergence of mammal-to-mammal transmission,” Michelle Wille, a wild bird virus researcher at the University of Sydney, told the CBC.
None of the workers, who wore protective clothing, on the farm appear to have become infected. But some scientists worry that minks could be a kind of springboard for the virus to make a leap to humans.
“This is incredibly concerning,” Tom Peacock, a virologist at Imperial College London, told Science Magazine. “This is a clear mechanism for the emergence of an H5 pandemic.”
Journalist Zeynep Tufekci, who has covered the COVID-19 pandemic extensively, wrote in a New York Times op-ed published this week entitled “An Even Deadlier Pandemic Could Soon Be Here.” She also spoke to Peacock, who noted that minks’ respiratory systems make them particularly good host species for viruses that can infect humans.
In her op-ed, Tufekci calls for a slew of precautions, including expanding testing capabilities and ramping up vaccine development and production. She also calls for mink farms to be closed – something some countries have already done due to a combination of concerns about animal cruelty and the fact that the farms have also been hotbeds for COVID-19.