March 10, 2023 – Nobody expected this consequence of climate change.
A team of European researchers digs within the Siberian permafrost 13 species of prehistoric viruses discovered and revivedAs the old frozen soil slowly loses its “perma” status attributable to rising temperatures, increasingly more microbes which have never come into contact with modern humans are resurfacing.
The researchers coined the – isn't it great – term “zombie viruses” to explain previously inactive viruses that had been frozen in ice for tens of hundreds of years – 27,000 to 48,500 years to be precise.
The first query is apparent: This is fascinating, but is it a very good idea? We are still coping with a particular mutating virus that our immune system has never encountered before.
The second query: What does this mean?
No people were harmed on this study
The short answer: The viruses observed here could only infect amoebae. However, in environments similar to permafrost, there are indeed viruses that may infect humans.
The possibility that in the future an unknown virus will appear out of nowhere and trigger one other pandemic shouldn't be necessarily zero.
“There is an objective risk, and it is increasing,” says Jean-Michel ClaveriePhD, the lead researcher and professor emeritus of genomics and bioinformatics at Aix-Marseille University in France. “However, we cannot quantify this probability, especially because we refuse to work with viruses that infect humans and animals and resuscitate them. That would be far too dangerous.”
According to the outcomes of Claverie and his team, viruses transmissible to humans and animals can actually survive for long periods of time deep within the permafrost.
“From our research, we can conclude that other viruses present in permafrost are probably still infectious,” says Claverie. “By sequencing the entire DNA, we can detect the presence of viruses similar to those that infect animals or humans today.”
However, the likelihood that, for instance, humans are exposed to thawed permafrost and there can be catastrophic consequences is low.”[The microbes] would quickly decay if exposed to heat, UV light and oxygen,” he says.
And in places like Siberia, where permafrost exists, it generally doesn't exist. Some science fiction-inspired fears (we're looking at you, fans of John Carpenter's The matter) are fairly unfounded. But if more people or businesses move into the areas where these microbes are released, the chances of a virus successfully infecting a host could be greater.
But what if …
So what would happen – hypothetically – if the next deadly virus to hit our planet came from the Arctic permafrost? Would we be even remotely prepared?
“There is a small risk that a frozen virus that is dug up could set off a chain of infection that eventually leads to humans,” says Adrian ListonPhD, immunologist and senior group leader at the Babraham Institute, a life sciences research institute at the University of Cambridge in the UK. Liston was not involved in the research discussed here. “On the one hand, we might don't have any pre-existing immunity to it, so the initial ability to fight the infection is low. On the opposite hand, the virus wouldn't be adapted to contaminate (modern) humans, so the prospect of a successful initial infection for the virus is incredibly low.”
Here's something many people don't understand: today's viruses and other infectious microbes are infectious only because they exist today. They have evolved to function within our modern immune systems – for better or for worse.
“'Entry events' are very rare and might affect human evolution,” says Liston. “Important examples are smallpox (a virus) and tuberculosis (a bacterium), which greatly affected human evolution once they invaded our species, choosing for the variety of immune system that might fight them and killing individuals with the 'improper' variety of immune system.”
And not all organisms are harmful.
“There are many, many microbes which might be helpful to humans,” says Liston. “But generally, these are microbes which have evolved over hundreds of thousands of years to work in harmony with our bodies, like our microbiome, or which were chosen over hundreds of years to perform useful tasks for us, like yeast in baking bread or brewing beer.”
It's unlikely that a random frozen microorganism will have a direct effect on us, but if it does, it's far more likely to be harmful, Liston says.
At least for now, we can rest assured that Claverie and his team have no plans to revive dangerous viruses or collect more samples. “Because of the Russian-Ukrainian war, all our collaborations have come to a halt. We are actually specializing in studying the viruses which might be already in our lab and understanding how they replicate and interact with their cellular hosts,” he says.
If anything, zombie viruses can at least remind us of the ever-increasing impact that climate change will have on our lives and our planet in the near future.
“The most significant message is that climate change will create unexpected problems,” says Liston. “It's not nearly weather changes, climate events and sea level rise. There can be a complete cascade of secondary problems. Climate change will almost actually result in recent infections, a few of which could lead on to pandemics.”