by An ongoing outbreak of a deadly bird flu strain has already killed millions of birds, and is becoming an even greater cause for concern as it spreads to mammalian species.
“This is an infection that has epidemic and pandemic potential,” Dr. Isaac Bogoch, a Toronto-based infectious disease specialist, told CBC. “I don’t know if people recognize how important this is.”
The H5N1 avian influenza virus is not 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 migratory wild birds to spread the virus to each other and to domestic birds along the way.
A rooster is 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 reaches poultry or egg farms, some of which have more than a million birds on the premises, the facility typically kills the entire flock to prevent further spread.
In the same time span, there have been 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. Since 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 Animal and Plant Health Agency, told the BBC he was “very aware of the risks” of bird flu becoming a pandemic among humans.
“This global spread is a concern,” he said. “We globally need to look for new strategies, those international associations, to control this disease. If we don’t solve the problem worldwide, we will continue to have that risk.”
A dead pelican, possibly infected with the H5N1 bird flu, is seen in Lima, Peru, on December 7, 2022.
In October, a large outbreak occurred at a mink fur farm in Spain. The researchers who described the outbreak in a paper published last month believe that wild birds initially transmitted H5N1 to the mink farm, 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 CBC.
None of the workers, who were wearing protective gear, at the farm appear to have been infected. But some scientists worry that the mink could be a kind of springboard for the virus to jump to humans.
“This is incredibly worrying,” Tom Peacock, a virologist at Imperial College London, told Science Magazine. “This is a clear mechanism for an H5 pandemic to start.”
Journalist Zeynep Tufekci, who has covered the COVID-19 pandemic extensively, wrote in a New York Times op-ed published this week titled “An Even Deadlier Pandemic Could Soon Be Here.” He also spoke with Peacock, who noted that mink’s respiratory systems make them particularly good host species for viruses that can infect humans.
In his opinion piece, Tufekci calls for a number of precautionary measures, including expanding testing capacities and increasing vaccine development and production. He is also calling 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 were also hotspots for COVID-19.
