COPENHAGEN (REUTERS) - Denmark's State Serum Institute, which deals with infectious diseases, has found mink-related versions of the coronavirus in 214 people since June, according to a report on its website updated on Thursday (Nov 5).

One strain of the mutated coronavirus, which has prompted Denmark to cull its entire herd of mink, has, however, only been found in 12 people and at five mink farms so far.

Denmark had announced strict new lockdown rules on Thursday in the north of the country after the authorities discovered a mutated coronavirus strain in minks bred in the region, prompting a nationwide cull that will devastate the large pelt industry.

The government said on Wednesday that it would cull all minks - up to 17 million - to prevent human contagion with a mutated coronavirus, which authorities said could be more resistant against future vaccines.

Seven municipalities in northern Denmark, home to most of the country's mink farms, will face restrictions on movement across county lines, while restaurants and bars will be closed, Prime Minister Mette Frederiksen told a press conference.

Schools will be closed and all public transport will be shut until Dec 3, she said, encouraging residents in the region to stay within their municipality and get tested.

For Denmark's mink pelt industry, which racked up exports of around US$800 million (S$1 billion) last year and employs 4,000 people, the cull could amount to a death knell. The industry association for Danish breeders called the move a "black day for Denmark".

"Of course, we must not be the cause of a new pandemic. We do not know the professional basis for this assessment and risk... but the government's decision is a disaster for the industry and Denmark," association chairman Tage Pedersen said.

At his family-owned mink farm west of the capital Copenhagen, 34-year-old Hans Henrik Jeppesen said he was devastated by the decision.

"This is a very, very sad situation for me and my family," he told Reuters. Mr Jeppesen's 36,000 minks have not been infected, but will be culled and skinned within the next 10 days.

Some lawmakers demanded to see the evidence behind such drastic action.

"We are asking to have it (the evidence) sent over, so we can assess the technical basis," a spokesman for the Liberal Party told broadcaster TV2 on Wednesday.

Outbreaks at mink farms have persisted in Denmark, Europe's largest producer and exporter of mink furs, despite repeated efforts to cull infected animals since June.

Animal rights groups welcomed the mass cull imposed by the government, and called for a general ban on what they said was an outdated industry.

"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," said Ms Joanna Swabe of Humane Society International.

In a meeting with the World Health Organisation and the European Centre for Disease Prevention and Control held earlier on Thursday, experts agreed with Denmark's strategy to tackle the situation, state epidemiologist Kare Molbak said.

WHO European regional director Hans Kluge said Denmark showed "determination and courage" in the face of a decision to cull its mink population, which has a "huge economic impact".

While no coronavirus has been detected at mink farms in Poland, another major mink pelt producer, authorities in Sweden on Thursday imposed restrictions on mink farms after infections were found.

However, they have not observed the mutation found in neighbouring Denmark.

Risk to future vaccines

In a report published on Wednesday, the State Serum Institute, the authority dealing with infectious diseases, said laboratory tests showed the new strain had mutations on its so-called spike protein, a part of the virus that invades and infects healthy cells.

That poses a risk to future Covid-19 vaccines, which are based on disabling the spike protein, the institute said.

Dr Ian Jones, a virology professor from Britain's University of Reading, said the virus would be expected to mutate in a new species.

"It must adapt to be able to use mink receptors to enter cells and so will modify the spike protein to enable this to happen efficiently," he explained.

"The danger is that the mutated virus could then spread back into man and evade any vaccine response which would have been designed to the original, non-mutated version of the spike protein, and not the mink-adapted version."

Authorities in Denmark said five cases of the new virus strain had been recorded at mink farms and 12 cases in humans.

Dr James Wood, a professor of veterinary medicine from Cambridge University, cautioned that the true implication of the changes in the spike protein had not yet been fully assessed by scientists.

"It is too early to say that the change will cause either vaccines or immunity to fail," he said.