The US announced the first cases of nCoV infection from mink

The Centers for Disease Control and Prevention (CDC) confirmed that during the first year of the pandemic, at least four people in Michigan contracted the version of nCoV found in ferrets.

Casey Barton Behravesh, director of the CDC's Office of Health, said virus samples were collected in October 2020. Of these, two are employees of a mink farm in Michigan and two have no connection to the farm.

The nCoV strain in mink may have appeared and spread more widely in the population.

According to the New York Times, these data suggest that the nCoV strain in mink may have appeared and spread more widely in the population in this area at that time. The strain they infected contains two mutations that were once thought to be adaptive markers of nCoV in ferrets. These mutations have been reported in ferrets raised in Europe and in humans associated with farms.

'This suggests a plausible hypothesis that farm workers became infected after coming into contact with ferrets carrying the virus. However, this cannot be conclusively proven. Because there are very few genetic sequences available from the community around the farm, we cannot know for sure whether the mutations came from the mink on the farm or appeared in the community first,' Dr. Barton Behravesh said.

Dr. Barton Behravesh said investigators had collected samples from animals and workers on the farm and people around. In March 2021, the CDC updated its official page noting that 'some people' have been infected with a version of nCoV that 'contains mutations specifically related to mink'. The agency stressed that 'data suggest that ferret-to-human transmission may have occurred' and that all patients have recovered.

Meanwhile, according to National Geographic, the first two people infected with nCoV from ferrets were identified on November 4, 2021, a few months before the CDC updated the data on the website. Dr Barton Behravesh said: 'CDC received genetic sequencing information indicating possible transmission from ferrets to humans by the end of 2020. Thereafter, the agency worked with relevant officials to clarify. '.

Mink-to-human transmission has also been reported in Denmark, the Netherlands and elsewhere.

In general, transmission of the virus from animals to humans is rare. Experts say humans are much more likely to spread nCoV to each other or to other species than the other way around.