The spread of the coronavirus among minks has become a major problem for mankind, as in their populations SARS-CoV-2 mutates rapidly and can then return to humans.
Genome analysis of these strains of the virus, which are widespread among minks, shows that they either rarely infect humans or do not occur in humans at all, writes Tomokazu Konishi of Akita Prefecture University in an article in the bioRxiv electronic library.
In late April, media in the Netherlands reported that local epidemiological services had found traces of the new coronavirus in the bodies of minks from two farms. According to the authorities, the source of the infection among the minks was infected workers in the enterprises.
The coronavirus was later detected on mink farms in the United States, Canada, Denmark and other countries, forcing authorities to massacre the animals and impose bans or restrictions on breeding.
An additional concern among scientists and authorities was that the virus mutated particularly rapidly once in a mink population and was easily transmitted from humans to animals and vice versa.
Assoc. Prof. Konishi analyzed in detail what mutations appear in the genome of the coronavirus when it enters a population of mink. He used the data to study the direction of the evolution of the new coronavirus, comparing changes in the genome of viruses in animal farms with SARS-CoV-2 strains circulating among residents of countries with infected farms.
The analysis showed that in several regions of Europe, viruses among mink and humans began to change along different evolutionary trajectories, which gradually made the former less contagious and dangerous to humans.
The expert claims that the strains currently circulating among the animals are not found among the population of the Netherlands and other countries where there were infected mink farms.
The strains that were transmitted by humans to minks and began to spread in late summer have now almost completely disappeared from the population.
At the same time, mortality from Kovid-19 is increasing. According to the researcher, this is proof that mink strains are less contagious and do less harm to humans than the variants of the virus that have recently circulated among humans.