WSAVA warns of corona mutation impact from mink

The WSAVA has warned the mutation of COVID-19 in Danish mink could have implications for the efficacy of human vaccines and lead to the spread of the virus to companion animals.

According to the World Health Organization (WHO), 214 human cases have been identified in Denmark with SARS-CoV-2 variants associated with farmed minks, including 12 cases with a unique variant.

Referred to as the “cluster 5” variant, the new strain of SARS-CoV-2 contains combinations or changes to the spike protein of the virus that have not previously been observed and have raised fears that Denmark could become the epicentre for the emergence of a new outbreak of the virus.

The discovery has prompted the Danish government to begin culling the nation’s estimated 17 million farmed mink. To date, five other countries – the Netherlands, Spain, Sweden, Italy and the US – have reported SARS-CoV-2 in farmed minks to the World Organisation for Animal Health.

‘Enormous implications’

Now the WSAVA has responded to the situation by urging Danish authorities to ensure the cull is handled humanely and in a way that reduces the risk of potential cross-species infection.

Past-president Shane Ryan said: “The culling of mink on farms in Denmark, should it continue, has enormous animal welfare implications, and the WSAVA calls on the relevant authorities to resolve the situation quickly and humanely.

“As an association, the WSAVA is focused on the veterinary health and welfare of companion animals, and the human-companion animal bond.

“While we are not commenting on the welfare and ethical issues around the farming of mink, we would like to make the following points.

“From reports seen, it is probable that on these farms the virus is being passed not only from humans to animals (mink), but also from the mink back to humans (zoonotic spread). Not only has the virus changed (mutated), but this variant and further mutations may have implications for vaccine efficacy.

“While there are no reports yet, there is the possibility for this mutation to spread to other animals, including companion animals.

“Disposal of the culled mink may present both an environmental and biological hazard. Should any of the dead mink be scavenged by wild or companion animals, there is the possibility that they may be exposed to the virus, with the potential of cross-species infection with the new virus strain of unknown virulence/pathogenicity in these species.”

Dr Ryan continued: “If resumed, the mass euthanasia will not only have a significant economic impact on the mink farmers, but will prove stressful for all involved. This includes not only the farmers, their families, but also any participating veterinarians, who are likely to need significant support.

“The COVID pandemic has clearly shown that animal health and welfare issues associated with intensive farming – and both the legal and illegal trade in wildlife – can have a major impact on human health and welfare.

“These issues require concerted, coordinated efforts from global one health leaders to mitigate risks of future pandemics, and to ensure both human and animal health.”

Genome sequencing

As well as culling millions of mink, Danish authorities have announced the expansion of genome sequencing of human and mink SARS-CoV-2 infections.

Members of the WHO SARS-CoV-2 Virus Evolution Working Group are working with Danish scientists to better understand the available results and collaborate on further studies.

It is understood that further scientific and laboratory studies will be undertaken to understand the implications of these viruses in terms of available SARS-CoV-2 diagnostics, therapeutics and vaccines in development.

While no mink farms exist in the UK, the BVA has highlighted the need for caution when handling any animals – including mustelids – to reduce the risks.

BVA senior vice-president Daniella Dos Santos said: “Cases of COVID-19 in animals remain rare and the most likely route of transmission continues to be from infected humans to animals.

“The UK does not have mink or other mustelids in such large numbers as Denmark as we don’t have mink farms. Therefore, the level of risk is very different.

“Our advice to vets working with any animals, including mustelids, at this time continues to be to implement strict hygiene measures when handling to minimise risk to human or animal health.”