The same team of French, Russian and German researchers previously isolated ancient viruses from permafrost and published their findings in 2015. This The concentration of fresh viruses suggests such pathogens are likely more common on the tundra than previously thought, they suggest in a preprint study they published last month on the BioRxiv website, a portal where many scientists post their Disseminating research results before they are included in a scientific journal.
“Every time we look, we’re going to find a virus,” said Jean-Michel Claverie, co-author of the study and emeritus professor of virology at Aix-Marseille Université in France, in a phone interview. “That’s a done deal. We know that every time we look for viruses, infectious viruses in the permafrost, we will find them.”
Although those they studied were only contagious to amoebas, the researchers said said there was a risk that other viruses that have been trapped in permafrost for millennia could spread to humans and other animals.
Virologists not involved in the research said the specter of future pandemics will emanate from the ranks of the Siberian steppe at the bottom of the current list public health threats. Most new — or old — viruses aren’t dangerous, and those that survive the freezer for thousands of years typically don’t fall into the category of coronaviruses and other highly infectious viruses that lead to pandemics, they said.
The results of the European team have not yet peer-reviewed. but independent virologists said that their The results seemed plausible and were based on the same Techniques that have led to different, verified results.
Risks from viruses piling up in the Arctic should be monitored, several scientists said. Smallpox, for example, has a genetic structure that can withstand long-term freezing, and if people come across the thawed corpses of smallpox victims, there’s a chance they’ll be reinfected. Other virus categories – like the coronaviruses that cause Covid-19 – are more vulnerable and less likely to survive the freezer.
“In nature, we have one big natural freezer, the Siberian permafrost,” said Paulo Verardi, virologist and chief of the Department of Pathobiology and Veterinary Sciences at the University of Connecticut. “And that can be a little bit concerning,” especially when pathogens are frozen in animals or humans, he said.
But, he said, “when you do the risk assessment, it’s very low,” he added. “We have a lot more to worry about right now.”
For the latest research, the European team took samples from several locations in Siberia over a number of years, starting in 2015. The viruses they found — of an unusually large type that infects amoebas — were last active in thousands, and in some cases tens of thousands, of years ago. Some of the samples were in the ground or in rivers, although one of the amoeba-targeted viruses was found in the frozen gut remains of a Siberian wolf at least 27,000 years ago, the team said.
The researchers used amoebas as “virus decoys,” they said, because they thought it would be a good way to look for viruses without spreading viruses that could spread to animals or humans. But they said that doesn’t mean these Viruses did not exist in the frozen tundra.
Siberia is warming at one of the fastest rates on Earth, about four times the global average. In recent summers, it has been ravaged by wildfires and temperatures reaching 100 degrees Fahrenheit. And its permafrost—soil so thoroughly cold it stays frozen through the summer—is thawing fast. This means that organisms trapped for millennia are now being uncovered, as prolonged thawing periods at the bottom surface cause objects trapped below to rise to the top.
Researchers say the likelihood of people tripping over human or animal carcasses is increasing, particularly in Russia, whose extreme northern reaches are more densely populated than Arctic regions elsewhere. The team collected some of their samples in Yakutsk, a regional capital and one of Russia’s fastest growing cities due to a mining boom.
The warming Permafrost has previously been blamed for outbreaks of infectious diseases. A 2016 anthrax outbreak hit a remote Siberian village and was linked to a 75-year-old reindeer carcass that emerged from the frozen ground. But anthrax, which isn’t a virus, isn’t unique to Siberia and is unlikely to cause widespread pandemics.
Many virologists are more concerned about viruses currently circulating among humans than the danger of more unusual ones from the permafrost.
New microbes are emerging or re-emerging all the time, Anthony S. Fauci, the director of the National Institute of Allergy and Infectious Diseases, told The Washington Post in 2015 when the permafrost researchers’ first findings were published.
“It’s a fact of our planet and of our existence,” he said. “The discovery of new viruses in the permafrost is not very different from any of this. Its relevance will depend on a series of unlikely events: The permafrost virus has to be able to infect humans, so it has to [cause disease], and it must be able to spread efficiently from person to person. That can happen, but is very unlikely.”
More problematic, say many virologists, are modern viruses that infect humans and lead to diseases that are sometimes difficult to control, such as Ebola, cholera, dengue and even the common flu. Viruses that cause disease in humans are unlikely to survive the repeated thawing and freezing cycle that occurs at the surface of permafrost. And the spread of mosquitoes and ticks, which has been linked to global warming, is more likely to infect people with pathogens, some experts say.
An extinct virus “appears to be a low risk compared to the large number of viruses circulating among vertebrates around the world that have proven to be a real threat in the past and where events similar to ours could happen in the future.” still do lack a framework to detect these early on,” said Colin Parrish, a virologist at Cornell University who is also president of the American Society for Virology.
Francis reported from London.
