An ongoing outbreak of a deadly strain of avian flu has already killed millions of birds, and it’s becoming an even bigger concern as it spreads to mammalian species.
“This is an infection that has epidemic and pandemic potential,” said Dr. Isaac Bogoch, an infectious disease specialist based in Toronto, with the CBC. “I don’t know if people realize how big this is.”
The H5N1 bird flu virus is not new. But before, it infected mostly birds on poultry farms. In 2020, however, a gene exchange 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 to poultry in their path.
A rooster is kept in a cage on a farm on January 23, 2023, in Austin, Texas. A strain of bird flu is becoming a concern as it spreads to mammalian species.
Since 2022, H5N1 has killed more than 58 million domestic birds such as chickens, ducks and turkeys in the United States alone. When the deadly virus strikes poultry or egg farms — some with more than a million birds on the premises — the facility usually culls the entire flock to prevent further spread.
In the same time, there were nearly 6,000 cases in wild birds in the US
Scientists have also found various wild mammals infected with the virus, including bears, foxes, otters and seals. As of October 2021, there have been five confirmed human cases worldwide and one death, according to the BBC.
Ian Brown, director of scientific services at the UK’s Animal and Plant Health Agency, told the BBC he was “very aware of the risks” of bird flu becoming a pandemic in humans.
“This global spread is a concern,” he said. “We worldwide need to look at new strategies, those international partnerships, to fight this disease. If we don’t solve the problem globally, we will always have that risk.”
A dead pelican, possibly infected with H5N1 bird flu, is seen in Lima, Peru on December 7, 2022.
In October, there was a major outbreak at a mink fur farm in Spain. Researchers who described the outbreak in a paper published last month believe that wild birds first transferred H5N1 to the mink farm, but once there, it spread from mink to mink.
“This outbreak is an indication that there is a real potential for mammal-to-mammal transmission to emerge,” Michelle Wille, a wild bird virus researcher at the University of Sydney, told the CBC.
None of the workers, who wore protective equipment, on the farm appear to be infected. But some scientists are concerned that mink could be a stepping stone for the virus to make the jump to humans.
“This is very worrying,” Tom Peacock, a virologist at Imperial College London, told Science Magazine. “This is a clear mechanism for the initiation of the H5 pandemic.”
“An Even Deadlier Pandemic Could Be Soon Here,” wrote journalist Zeynep Tufekci, who has covered the COVID-19 pandemic extensively, in an opinion piece in the New York Times published this week. She also spoke with Peacock, who noted that the respiratory systems of minks make them a particularly good host species for viruses that can infect humans.
In his op-ed, Tufekci calls for precautionary measures, including expanding testing capabilities and increasing vaccine development and production. She also calls for the closure of mink farms – something some countries have already done due to a combination of animal cruelty concerns and the fact that the farms were also hotbeds for COVID-19.