Bird flu on mink farms is a real threat

As Finland continues to grapple with a record-setting avian flu outbreak on at least five mink farms, resulting in the slaughter of tens of thousands of animals, scientists again warn that the H5N1 virus responsible for bird flu could mutate among captive mink populations into a form infectious to humans. While this seems far removed from our daily lives, let’s not forget that many of us barely registered news of a mysterious virus outbreak in China in early 2020 before it swept the globe.

COVID-19 has killed nearly 7 million people worldwide, and the head of the World Health Organization warns of future pathogens with “even deadlier potential.” Many scientists point to mink farms, in particular, as dangerous petri dishes for incubating the next pandemic virus.

Unfortunately, the U.S. government has largely ignored this clear hazard. These operations, where mink are bred and raised in crowded, filthy conditions to be killed for their pelts, could become reservoirs where respiratory viruses incubate and mutate as they jump between mink and other species, including rodents, cats, dogs, and humans.

Following the lead of more than a dozen European countries that have either banned or are in the process of banning fur farms, Congress must act swiftly to shut down mink farms.

One solution is legislation recently introduced by Rep. Adriano Espaillat (D-NY) that would phase out mink farming and reimburse mink farmers for the full value of their farms, helping them transition away from an industry struggling due to shrinking consumer demand. An estimated 100 mink farms remain in 16 states, and last year was the fur industry’s worst on record.

Mink pose a high risk to humans because their upper respiratory tracts are physiologically similar to ours, which means that they can become infected by some of the same viruses — and potentially transmit dangerous variants back to people.

To date, millions of mink have contracted COVID-19, and mink have passed a mutated form of the virus back to humans in at least six countries, including the United States. Four people in Michigan were infected with a unique COVID-19 strain traced back to mink, including community members who had no ties to the mink farm. This type of “spillback” event, in which a pathogen spills over from one species to another and then back again, is an urgent crisis that we ignore at our own peril.

Conditions on fur farms, which typically pack thousands of mink into barren pens barely large enough for them to move around, enable the rapid spread of pathogens; in late 2020, for instance, Denmark ordered the slaughter of its entire farmed mink population (about 17 million) in response to COVID-19 outbreaks at 200 farms.

Clever and agile, mink frequently escape their captors, becoming integrated into the habitat around the farms and creating another venue for pathogens to spread. In December 2020, a wild mink captured near a mink farm in Utah tested positive for a variant of COVID-19 indistinguishable from the virus found in nearby farmed mink. One study found that 82% of wild mink living in a mink farming region of Ontario carried antibodies indicating they had, at some point, contracted amdoparvovirus 1 — another deadly virus carried by many captive mink — while wild mink living in a region without mink farms lacked such antibodies.

Until Congress passes Espaillat's legislation, we risk fostering ecosystems in which dangerous pathogens endlessly circulate, spawning new variants and undermining existing pandemic-fighting tools.

This guest essay reflects the view of Kate Dylewsky, assistant director for government affairs at the Animal Welfare Institute.