A new strain of Covid is spreading through Danish fur farms
Denmark has more mink than people. About 17 million of the weasel-like creatures (the mink, not the Danes) live out their lives on Danish fur farms. That’s an estimate that will soon have be revised downwards — to zero.
The Danish government has ordered the slaughter of the entire national mink herd. That’s not for animal welfare reasons, but to control an outbreak of Covid.
Yes, Covid. Mink can get SARS-CoV-2 from us — and, caged up as they are, they then give it to each other. Eradication attempts have failed — hence the government order.
If you think that’s grim, then I’m afraid it gets worse. The real cause for alarm is that the virus running rampant through the mink population has mutated. It’s reported that the (human) antibody response to the virus could be weaker if faced with the mink mutant strain. And because the virus can move in the other direction — spreading from mink back into the human population, that could be bad news. For instance, a vaccine that’s effective against the standard version of the virus could be less effective against the mutant one.
Eek, as the mink might say.
But according to Francois Balloux, director of the UCL Genetics Institute, these fears are wildly overblown:
Nevertheless, the Danish government is worried enough to kill all the mink — and, furthermore, to impose extra lockdown measures on those parts of the parts of country where the fur farms are located.
If I understand him correctly, Professor Balloux says that the enormous pool of the virus in the human population is mutating all the time anyway and thus if this process were capable of creating a super-virus then it would have happened already.
I have the merest fraction of Balloux’s expertise, but I recall from my undergrad biology that evolution is not a self-contained process for any organism, but a response to the environment it lives in and especially to the other species it interacts with. Though humans and mink are both mammals they’re also rather different. It therefore doesn’t seem impossible that a shift from one host species to the other might result in mutations that wouldn’t otherwise have happened.
Our intensive, industrialised farming of other species provides our pathogens with a series of sandboxes in which they can proliferate uninterrupted by social distancing, while getting to experience a new set of environmental conditions. If ever there was an opportunity to evolve variations that wouldn’t occur in human hosts alone, then it’s surely down on the factory farm.