Denmark will cull its mink population of up to 17 million after a new mutation of the coronavirus found in the animals spread to humans, the prime minister said on Wednesday. The new strain may have a negative impact on future vaccines, according to initial findings.Six countries have reported cases of SARS-CoV-2 in farmed minks, including Denmark, the Netherlands, Spain, Sweden, Italy and the US, according to the WHO. Health authorities found virus strains in humans and in mink which showed decreased sensitivity against antibodies, potentially lowering the efficacy of future vaccines, Prime Minister Mette Frederiksen said."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," Frederiksen told a news conference.The findings, which have been shared with the World Health Organization and the European Centre for Disease Prevention and Control, were based on laboratory tests by the State Serum Institute, the Danish authority dealing with infectious diseases.The head of the WHO's emergencies program, Mike Ryan, called on Friday for full-scale scientific investigations of the complex issue of humans - outside China - infecting mink which in turn transmitted the virus back to humans."We have been informed by Denmark of a number of persons infected with coronavirus from mink, with some genetic changes in the virus," WHO said in a statement emailed to Reuters in Geneva. "The Danish authorities are investigating the epidemiological and virological significance of these findings."In a press statement, the WHO stressed that "the implications of the identified changes in this variant are not yet well understood" and that "further scientific and laboratory-based studies are required to verify preliminary findings reported and to understand any potential implications of this finding in terms of diagnostics, therapeutics and vaccines in development."The WHO warned that it is a "concern" when any animal virus spills in to the human population or when an animal population could contribute to amplifying and spreading a virus affecting humans. "As viruses move between human and animal populations, genetic modifications in the virus can occur," added the WHO.Authorities in Denmark said five cases of the new virus strain had been recorded on mink farms and 12 cases in humans, and that there were between 15 million and 17 million mink in the country. Overall, 214 human cases of COVID-19 associated with mink farms have been identified in Denmark, although not all have been associated with the new virus strain.Outbreaks at mink farms have persisted in the Nordic country, the world's largest producer of mink furs, despite repeated efforts to cull infected animals since June.Denmark's police, army and home guard will be deployed to speed up the culling process, Frederiksen said.Christian Sonne, professor of Veterinary and Wildlife Medicine at Aarhus University, said in an email he believed culling the herd now as a precautionary measure was a sound decision and could prevent a future outbreak that would be more difficult to control. Sonne co-authored a letter published in the journal Science last week calling for the cull."China, Denmark, and Poland should support and extend the immediate and complete ban of mink production," Sonne and his co-authors wrote last week.Tougher lockdown restrictions and intensified tracing efforts will be implemented to contain the virus in some areas of Northern Denmark, home to a large number of mink farms, authorities said."The worst case scenario is a new pandemic, starting all over again out of Denmark," said Kare Molbak, director at the State Serum Institute.Israeli animal rights group Animals Now issued a statement commenting on the "mass and painful" culling of the mink herd, hoping it would "mark the end of Denmark's fur trade industry.""The coronavirus came to humans because of eating wild animals, so the development of this frightening mutation is not surprising," the statement read. "When animals are kept in filthy and densly-packed conditions, it is a breeding ground for epidemic outbreaks."They added that "We are happy that at least in Israel, the fur trade is coming to an end, and we are waiting on a bill drafted by [Environmental Protection Minister Gila Gamliel] to be made law and enforced."This is not the first time animals have been culled due to coronavirus outbreaks linked to the fur trade, with minks in Spain and the Netherlands having been culled just last month.