Should we be concerned about the contamination of mink by a mutated Covid-19?

A mink farm on a farm in Denmark.

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• In Denmark, farmed mink carry a mutating version of the coronavirus.

• A mutated version of the virus which is transmissible to humans, since a dozen human contaminations have been identified in the kingdom.

• Fearing that this mutation could affect the effectiveness of a future anti-Covid vaccine, Denmark has opted to slaughter all of the country's mink farms, i.e. 15 to 17 million animals.

They will all be slaughtered as a health precaution.

Denmark, the world's largest exporter of mink skins, sparked concern on Wednesday by announcing the mass slaughter of all mink in the kingdom - 15 to 17 million heads - and the closure of part of the country for at least four weeks.

A decision taken by Copenhagen after the presence of a mutated version of SARS-CoV2 was detected in several farms of this small furry mammal.

This mutation of the coronavirus transmissible to humans, called “cluster 5”, has already been detected in twelve people, including eleven cases in Jutland, a region where several farms are concentrated.

“We are taking the necessary and appropriate measures” in the face of a “worrying” development, Foreign Minister Jeppe Kofod said on Friday.

The kingdom considers this mutation of the coronavirus from mink problematic, believing that it could threaten the effectiveness of a future human vaccine.

Why does SARS-CoV2 mutate, and is it dangerous?

From January,

raised the question of the dangerousness of a changing coronavirus.

If SARS-CoV2 mutates, does that make it a more aggressive virus?

Not necessarily, then the Institut Pasteur told us.

"Coronaviruses are a family of viruses which we know can mutate and evolve rapidly, as was the case with SARS," explained Sylvie Behillil, deputy head of the National Reference Center for Respiratory Infections Viruses (CNR ) of the Institut Pasteur.

“Mutations can cause a variety of different effects.

This can increase the contagiousness of the virus by making it more easily transmitted between people, or make it more virulent.

But it can also have the opposite effect and make it less virulent, ”added the researcher, conceding that everything still remains to be discovered about this emerging virus.

Because we already knew that it is normal for a virus to mutate.

When it enters a cell, it replicates.

Understand: it copies itself in order to propagate itself.

With each replication, errors occur in the copy of its genome, like a computer "bug".

But this error may or may not have a greater or lesser impact on the way he behaves.

The mutation can be "favorable" to the virus (it helps it to survive better), or "unfavorable" (it weakens it for example, which is then more favorable for us).

This is called natural selection.

RNA viruses (genetic material close to DNA), such as SARS-CoV-2, mutate faster than DNA viruses because their encoding errors are more frequent.

However, coronaviruses mutate more slowly than other RNA viruses.

So far, SARS-Cov-2, for example, mutates half as quickly as influenza and four times slower than HIV, according to Emma Hodcroft, molecular epidemiologist at the University of Basel (Switzerland), recently cited in the

journal

.

Scientists even consider the coronavirus to be genetically relatively stable.

But what matters is whether these mutations have any noticeable effects.

However, for the moment, there is no clear indication that the virus has mutated in such a way as to significantly modify its effects on humans.

One thing is certain: SARS-CoV2 is no exception to the rule and "mutates all the time", explained in September Marie-Paule Kieny, virologist, director of research at Inserm, during a hearing in the Senate .

Does the mutation observed in mink in Denmark represent a threat to the effectiveness of a future vaccine?

The World Health Organization (WHO) indicates that it is monitoring the situation closely and being in contact with Copenhagen.

And according to the explanations of the Danish authorities, "Cluster 5", the strain of which was identified at the beginning of the week, does not result in more serious effects in humans.

This mutation, however, implies a lower efficiency of human antibodies, which threatens the development of a vaccine against Covid-19, the subject of a race against time across the world and of all hopes to stem the pandemic.

According to Danish Minister of Health Magnus Heunicke, "research has shown that mutations may affect current candidates for a vaccine against Covid-19".

In North Jutland, health authorities estimate that around 5% of patients could be carriers of this strain, but no recent cases have been reported, making the proof of the actual circulation of the mutated virus uncertain.

For Viggo Andreasen, professor of epidemiology at the University of Roskilde, this mutation "has a fairly good chance" of disappearing, provided it is effectively combated.

"It may take time," "about a month," he said.

But to find out more, experts call on Denmark to disseminate more scientific data to better assess the mutation and its consequences.

Should we be concerned about a risk of contamination from French mink farms?

If the Danes are the world's leading exporters of mink, France also has farms.

She therefore increased her level of vigilance.

"We set up surveillance in the summer", after an alert from the Dutch authorities reporting in early June of contamination of mink by Covid-19, said the Ministry of Ecological Transition, in charge of the four farms French.

Mortality surveillance has been put in place and "biosecurity measures are already being strengthened in these farms", the same source added.

"And we will take the appropriate measures according to the evolution of the situation".

According to ANSES recommendations, PCR and serological analyzes (to detect the presence of the virus and antibodies respectively) will be carried out "in the form of a scientific study" in November and December, the period of seasonal slaughter of mink raised for their purpose. fur, the ministry said.

Beyond the health risk linked to the potential transmission by mink of Covid-19, the four French farms have long been denounced by animal rights activists, who demand their closure.

And they won their case last September: they must close "within five years" in France, according to the announcements made in September by the Minister for the Ecological Transition, Barbara Pompili.

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Coronavirus in Denmark: Millions of mink to be slaughtered because of threatening mutation in virus

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The coronavirus would be able to mutate, should we be worried?

• epidemic

• Coronavirus

• Health

• Covid 19

• Animals

• Denmark