A mutated variation of the virus found in mink being farmed for their fur has also been found in 12 people in the country, leading to a government order for Denmark’s entire mink population of 17 million to be killed.
Mike Ryan, the WHO's top emergencies expert, said the organisation would complete a risk assessment of the incident and share it with members within hours.
“There's always the potential that this can come back to humans," Mr Ryan said. “That is a concern because mammal species like mink are very good hosts, and the virus can evolve within those species, especially if they are in large numbers packed closely together.”
The spread of the mutated virus has raised concerns that the potential efficacy of vaccines in development could be weakened.
Animal-welfare campaigners said the risk of keeping “these virus reservoirs” – fur farms - operating was far too great, welcoming the cull.
Denmark is one of the world’s largest fur producers, exporting most of its fur to Asian markets.
Several strains of mink-related coronavirus were found on 207 out of the country’s 1,139 fur farms.
Four of the people infected were linked to three of the farms where one mutated strain was found.
More than a quarter million Danes have been put under lockdown in a northern region of the country as a result of the new strain being discovered.
Joanna Swabe, of Humane Society International/Europe, said: “A total shut-down of all Danish mink fur farms amidst spiralling Covid-19 infections is a significant development. Although not a ban on fur farming, this move signals the end of suffering for millions of animals confined to small wire cages on Danish fur farms solely for the purposes of a trivial fur fashion that no-one needs.
“We commend the Danish prime minister on her decision to take such an essential and science-led step to protect citizens from the coronavirus and ensure the effectiveness of any vaccine is not compromised by mutations in the virus from its mink hosts.
“The risk of keeping these virus reservoirs operating is far too great.”
A decline in the public demand for fur fashion has led to a significant drop in pelt prices and stockpiles of fur skins going unsold at auctions, she said, and urged the Danish government to help fur farmers switch to other activities.
Prof James Wood, head of the Department of Veterinary Medicine at the University of Cambridge, said it was highly likely that the transmission of the mutated strain to hundreds of people was driven by person-to-person transmission rather than mink-to-person transmission.
“Thus culling mink may well not in itself cause the strain to disappear, but may stop further mutant strains from developing in that species,” he said.
Mimi Bekhechi, of animal-rights group Peta, said: “Fur farms packed with sick, stressed, suffering animals are revolting places – they are dangerous breeding grounds for diseases and have been identified as Covid-19 hot spots.
“Peta is urging Denmark to ban these pandemic petri dishes immediately – because no one needs a mink coat, but we do need an effective vaccine and an ethical society.”
Dr Swabe added: “Although the death of millions of mink - whether culled for COVID-19 or killed for fur - is an animal welfare tragedy, fur farmers will now have a clear opportunity to pivot away from this cruel and dying industry.”
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