The Danish government will slaughter millions of mink at more than 1,000 farms, citing concerns that a mutation in the novel coronavirus that has infected the mink could possibly interfere with the effectiveness of a vaccine for humans.
Prime Minister Mette Frederiksen made the announcement at a news conference on Wednesday. There are 15 million or more mink in Denmark, which is one of the world’s major exporters of mink furs. She said the armed forces would be involved in the culling of mink.
Kare Molbak, the head of the State Serum Institute, the government’s public health and infectious disease arm, warned at the news conference that a mutation could interfere with the effectiveness of future vaccines. The government has notified the World Health Organization of the virus mutation, and also said 12 people in its Jutland region are known to have it and that it shows a weak reaction to antibodies, according to news reports.
The W. H.O. acknowledged by email that it had been “informed by Denmark of a number of persons infected with coronavirus from mink, with some genetic changes in the virus.” The W.H.O. said that Denmark was “investigating the epidemiological and virological significance of these findings, and culling the mink population. We are in touch with them to find more about this event.”
Without published reports on the nature of the mutation or how the virus variant was tested, research scientists outside Denmark who study the virus were left somewhat in the dark. Dr. Stanley Perlman, a microbiologist at the University of Iowa and a specialist on the novel coronavirus, said he could not evaluate the Danish statements without more information.
Dr. Jonathan Epstein, vice president for science and outreach at the EcoHealth Alliance, a conservation organization, said he had not seen any details so far, but, “Someone would have to release the sequences soon, and the evolutionary biologists will be all over it.”
On Twitter, Emma Hodcroft, a geneticist at the University of Basel, Switzerland, who is tracking the spread of the novel coronavirus, urged caution. “Don’t panic,” Dr. Hodcroft tweeted. “Scientists will update when we have more info.”
In September, Dutch scientists reported in a paper that has not yet been peer-reviewed that the virus was jumping between mink and humans. In Denmark, the government is describing a version of the virus that migrated from mink to humans.
The coronavirus mutates slowly but regularly, and a different variant of the virus would not, in itself, be cause for concern, experts have said.
Researchers have studied one mutation labeled D614G in the spike protein of the virus which may increase transmission. They concluded that there is no evidence so far that the particular mutation increases virulence or would affect the workings of a vaccine.
Denmark had already begun killing all mink at 400 farms which were either infected, or close enough to infected farms to cause concern. The killing of all mink will wipe out the industry, perhaps for years.
Mink are in the weasel family, along with ferrets, which are easily infected with the coronavirus. Ferrets appear to suffer mild symptoms. Mink, which are kept in crowded conditions ideal for spreading a virus, can become quite sick and die. Mink have been infected in other countries as well, including the Netherlands and some U.S. states. Thousands of mink were killed in Utah because of a coronavirus outbreak, but authorities there said there it did not appear that the mink transmitted the virus to humans, but the opposite.
Many conservation scientists have become concerned about the spread of the virus to animal populations, like chimpanzees, which are believed to be susceptible, although cases have not been identified yet. Groups of researchers are testing bats and pets and wild animals in the United States.
Researchers are also concerned about what occurs when the virus moves from one species to another and may acquire changes, or mutations. While most such changes are not likely to be a problem for humans, there is always the chance that strains of the virus could become more infectious or more virulent.
Animal Protection Denmark, an advocacy group, recommended a long-term solution to the problem of mink and coronavirus: “The right decision would be to end mink farming entirely and help farmers into other occupation that does not jeopardize public health and animal welfare.”