According to government officials in Denmark, mink raised on Danish farms carry a mutated version of the SARS-CoV-2 virus that is less sensitive to antibodies, which they say might thwart vaccine development. Minks readily host and spread the virus and because this strain has now been found in humans, the prime minister announced on November 4 that Denmark would cull the entire stock of its mink farms, which equates to about 17 million animals spread across 1,000 farms.
So far, five human cases of this strain are linked to mink farms, and 12 people have become infected in all. According to reports, the Danish government has shared its findings with the World Health Organization (WHO) and the European Centre for Disease Prevention and Control. “We have been informed by Denmark of a number of persons infected with coronavirus from mink, with some genetic changes in the virus,” a representative from the WHO tells Reuters. “The Danish authorities are investigating the epidemiological and virological significance of these findings.”
The full genetic details of this strain and the serological findings of patients have not been published yet.
“Someone would have to release the sequences soon, and the evolutionary biologists will be all over it,” Jonathan Epstein, the vice president of science and outreach at EcoHealth Alliance who was not involved with the government report, tells The New York Times.
According to the prime minister, this strain makes it harder for the body to create antibodies against it, possibly undermining vaccines currently in development, although there is no evidence to show that is the case.
Denmark has had hundreds of COVID-19 cases tied to mink farms throughout the pandemic, and the cull will now follow in the footsteps of similar efforts to reduce transmission through minks in Spain and the Netherlands. As Denmark leads the world in mink production, it will have to kill 150 times as many animals as the other countries, which will likely crash the industry for years to come, according to The Guardian.
“We have a great responsibility towards our own population, but with the mutation that has now been found, we have an even greater responsibility for the rest of the world as well,” Danish Prime Minister Mette Frederiksen said at a news conference Wednesday, Reuters reports.
A letter published in Science on October 30 calls for the ban of what is described as “unsustainable mink production” in Denmark and other countries. While the letter mainly focuses on COVID-19 outbreaks worldwide linked to mink farms, it also cites other zoonotic diseases that mink are known to harbor.
According to the BBC, ongoing studies are trying to determine why minks are such good hosts for SARS-CoV-2.