DrEnmark set the alarm bells this week by announcing that it is culling the nation’s entire mink flock – the largest in the world – to stop the spread of SARS-CoV-2 in valuable furs due to potentially dangerous mutations.
The leaps of viruses between species make scientists nervous – as do suggestions about potentially important mutations that result from those hops. In this case, the Danish authorities say they have found some genetic changes that may undermine the effectiveness of Covid-19 vaccines currently in development.
But is this latest development in the Covid-19 saga a cause for deep concern? Several experts consulted by STAT suggested that the answer to this question may not be.
“This hits all the scary buttons,” said Carl Bergstrom, an evolutionary biologist at the University of Washington. But Bergstrom and others have argued that while the virus’s tendency to infect mink bears is unlikely to lead to a nightmarish strain that is more effective in infecting people than the current human virus.
“I don’t think a strain that adapts to mink poses a greater risk to humans,” said Francois Ballou, director of the Institute of Genetics at University College London.
We can never rule out anything, but in principle it should not. The transmission should definitely not be increased. I don’t see any good reason why the virus should be more severe.
Let’s take a look at what is known about the Danish situation, why inter-species jumps are making scientists anxious, whether mutations are likely to affect vaccine efficacy, and why Palux thinks this situation is “fantastically interesting.”
What happens in the country of Denmark?
Denmark is the largest producer of mink in the world. Around 28% of the supply produces this luxurious furs.
Unfortunately, mink is susceptible to SARS-2 infection, a fact that emerged in April when Holland An outbreak has been reported In mink plantations there. Infected humans working on farms transmit the virus to captive minke animals, which are found in close quarters are ideal for the quick transmission from mink to mink.
From time to time, mink infects people – a phenomenon recorded in both Netherlands And in Denmark. The current situation, The Danish Ministry of Environment and Food said that the country will kill its entire herd – estimated at 17 million animals – after discovering mutations in viruses from the mink that it believes will allow those viruses to evade the immune protection generated by the Covid-19 virus vaccine.
Why do they think mutated viruses will escape vaccines?
Experts from outside the country are not clear on the basis of this claim. Marion Copmans, head of virology at the Erasmus Medical Center in Rotterdam, the Netherlands, said that although there is some information released about the mutations that have been recorded, support for such a bold claim is not yet sufficient. Virus analyzes of Dutch mink outbreaks were performed.
“That’s a very big statement,” said Copmans. “One mutation, I don’t expect it to have this dramatic effect.”
Emma Hodcroft, a molecular epidemiologist at the Institute for Social and Preventive Medicine in Bern, Switzerland, said outside experts did not have the genetic sequence data to peruse. But Denmark uploaded 500 gene sequences to databases open to scientists around the world on Thursday, and is expected to add hundreds more in the coming days.
Experts will look at these sequences for what the Danes saw and try to determine the effect that these mutations might have if the viruses they contained infect humans.
For now, however, Hodcroft agrees with Koepmans. “It almost never happens to be a simple story of one mutation and all of your vaccines stop working.”
She is, honestly, more interested in how she handles the advertisement than she is about the results themselves. “It puts scientists and the public in a really difficult position when we have statements like this that we have very little information or context,” Hodcroft said. “These things are not primarily black and white.”
How many species do they jump anyway?
Species jumping always makes scientists nervous. One of those events, after all, is how we ended up with the Covid-19 pandemic.
Viruses that usually infect one type of animal – let’s use bats as an example – that find their way to other species can cause severe disease in new species if the virus is able to transmit efficiently. Viruses can become entrenched – endemic – in new species.
For example, the four coronaviruses – SARS-2 cousins - that cause the common cold are thought to have spread from other species to humans at some point in the past. Events spread of the influenza virus – from poultry or pigs – occur from time to time. The H1N1 pandemic emerged in 2009 when the influenza virus that was circulating in pigs began to infect people.
Bergstrom said that after years of dealing with viral fallout such as the Ebola outbreak and influenza pandemic, in addition to previous leaps of coronavirus such as the SARS outbreak in 2003, people are ready to worry about these events.
But he said that was a different situation. It is not a hopping virus unknown to humans of an animal type. In this case, the virus that has already adapted to spread among people has jumped into the mink and now it jumps again from time to time.
Bergstrom believes it is wise for the Danish government to execute the herd of mink. But he is not sure that the changes made in the mink are likely to make the virus worse for people.
We used to feel fear before a pandemic when something from a distant species comes to a closer one. Our intuition is not quite a good fit for what happens in the middle of a pandemic when something from us moves to distant creatures and then returns, ”he said.
Palux and others suggested that changes observed in mink viruses may be a sign of the virus adapting to infect mink animals – potentially making the viruses less effective in humans over time.
Capture indirect effects in real time
Palux links the risk that this spread to humans is “really really small”.
But he said it’s exceptional to be able to capture in real time what is happening when fallout occurs, and map out the genetic changes from the start.
Usually when events like this happen, humans only learn what happens as the virus adapts to spread between humans. For example, the early changes that made SARS-CoV-2 so able to pass from still unknown animal species to humans were never noticed.
It’s totally exceptional, ”said Ballou. “We are always [too] Late.”