Scientists have discovered the “zombie” virus that was present in the Arctic ice 48,500 years ago

The increasing temperatures prevailing in the Arctic cause this to happen Thawing of the area’s permanent ice layer (permafrost) – that is, the frozen layer that lies underground – which is likely to raise viruses that may endanger human and animal health after remaining dormant for tens of thousands of years.

The scenario of a pandemic breaking out from a disease from the distant past might sound like a science fiction movie, however Scientists warn that there are risks, albeit low, is currently undervalued. according to CNNand chemical and radioactive waste dating back to the Cold War, which can harm wildlife and disrupt ecosystems, as well as be released as snow melts and snow melts.

“There’s a lot going on with troubling permafrost, and it really shows why it’s so important to keep as much permafrost frozen as possible,” said Kimberly Miner, a climate scientist at NASA’s Gas Propulsion Laboratory at Caltech in California. Pasadena, California.

Permafrost covers one-fifth of the northern hemisphere, having supported arctic tundra and boreal forests in Alaska, Canada and Russia for thousands of years. It serves as a time capsule, preserving – in addition to ancient viruses – the The mummified remains of many extinct animals Scientists have been able to retrieve and study them in recent years, including small cave lions and woolly rhinos.

The reason permafrost is such a good storage medium isn’t just because it’s cold – it’s an oxygen-free environment that light can’t penetrate. But temperatures in the Arctic today are rising four times faster than in the rest of the planet, thinning its uppermost layer permafrost in the area.

To better understand the risks posed by frozen viruses, Jean-Michel Claverie, Professor Emeritus of Medicine and Genomics at Aix-Marseille University School of Medicine in Marseille, FranceExamination of samples taken from permafrost in Siberia to determine if they contain any viral particles They are still contagious. He’s been researching what he calls “zombie viruses” – and he’s found some.

Virus catcher

Claverie studies a particular type of virus that he first discovered in 2003. They are known as giant viruses, which are much larger than standard types and can be seen with a normal light microscope rather than a more powerful electron microscope–making them a good model for this kind of lab work.

His efforts to detect viruses frozen in permafrost were inspired in part by a group of Russian scientists In 2012, a wildflower was revived from the tissue of a 30,000-year-old seed Found in a squirrel hole. Since then, scientists have also succeeded in bringing ancient young animals back to life.

In 2014, he was able to revive a virus he and his team had isolated from permafrost, making it infectious for the first time in 30,000 years, by introducing it into cultured cells. For safety reasons, he chose to study a virus that could only target single-celled amoebae, not animals or humans.

He repeated the feat in 2015, isolating a different type of virus that also targeted amoebae. In their latest research, published February 18 in the journal Viruses, Claverie and his team isolated different strains of an ancient virus from multiple permafrost samples taken from seven different parts of Siberia and showed that each could infect cultured amoeba cells. .

These strains represent the latter Five new virus familiesIn addition to the two I had previously. The oldest was about 48,500 years oldbased on radiometric dating of soils, and come from a soil sample taken from a subterranean lake 16 meters below the surface. latest samplesFound in the stomach contents and fur of the remains of woolly mammoths 27,000 years.

The fact that viruses that infect amoebas are still infectious after such a long time Indication of a potentially larger problemClavery said. He is afraid that people will view his research as a scientific curiosity and They do not see the prospect of ancient viruses returning to life as a serious threat to public health.

“We view these viruses that infect amoebae as surrogates for all the other possible viruses that might be present in the permafrost,” Claverie told CNN.

“We see traces of many, many, many other viruses,” he added. “So we know they exist. We don’t know for sure that they’re still alive. But our reasoning is that if the amoeba viruses are still alive, there’s no reason to rule out that other viruses wouldn’t be alive and able to infect their hosts.” .

There are no previous data on human infection

Traces of viruses and bacteria that can infect humans have been found preserved in the permafrost.

A lung sample from a woman extracted in 1997 from the permafrost in a village on Alaska’s Seward Peninsula It contained genomic material from the influenza strain responsible for the 1918 pandemic. In 2012, scientists confirmed that the 300-year-old mummified remains of a woman buried in Siberia contained the genetic signature of the virus that causes smallpox.

The Siberian carbon release that affected dozens of people and more than 2,000 reindeer between July and August 2016 has also been linked to the melt. permafrost During very hot summers, allowing ancient spores of Bacillus anthracis to emerge from ancient burial sites or animal carcasses.

There should be Better control of potential pathogen risks in de-icing of permafrost, but he warned against risks.

“You have to remember that our immune defenses have evolved in close contact with the microbiological environment,” said Evengaard, a member of CLINF’s Nordic Center of Excellence, a group that researches the effects of climate change on the spread of infectious diseases in humans and animals in northern regions.

“If there’s a virus hiding in the permafrost that we haven’t dealt with in thousands of years, that could mean that our immune defenses aren’t up to the scratch,” he said. “It is right to respect the situation and be proactive rather than just reactive. The way to fight fear is to have knowledge.”

Chances of spreading the virus

Scientists do not know how long these viruses can last They remain infectious when exposed to current conditions, or how likely the virus is to encounter a suitable host. Not all viruses are pathogens that can cause disease – some are benign or even beneficial to their hosts. And despite being home to 3.6 million people, the Arctic is still a sparsely populated place, which has made The risk of human exposure to ancient viruses is very small.

However, Clavery said, “The risk will certainly increase in the context of global warming, as the melting of permafrost will continue to accelerate and more people will live in the Arctic in the wake of industrial projects.”

And Clavery is not alone in warning that the region could become a breeding ground for a spillover event – ​​when that is the case. The virus moves to a new host and begins to spread.

Last year, a team of scientists published research on soil and lake sediment samples taken from Lake Hazen, a freshwater lake in Canada located just inside the Arctic Circle. They sequenced the genetic material in the sediments to trace the fingerprints of viruses and the genomes of potential hosts — plants and animals — in the area.

Using a computational model analysis, they suggested that the risk of viruses passing on to new hosts was higher at sites that were close to places where large amounts of water flowed from glaciers into the lake — a scenario that, like climate, is becoming increasingly likely. to heat up.

The unknown consequences

A miner from NASA’s Jet Propulsion Laboratory said that identifying viruses and other hazards present in the warming permafrost is the first step in understanding the threat they pose to the Arctic. Other challenges include determining where, when, how quickly and how much permafrost is thawing.

Thawing can be a gradual process only a few centimeters per decade, But it also happens faster, as in Massive landslides that can suddenly reveal deep and ancient layers from permafrost. This process also releases methane and carbon dioxide into the atmosphere – a factor from climate change are underestimated.

Miner listed a number of potential hazards currently “frozen” in Arctic permafrost in a 2021 paper published in the scientific journal Nature Climate Change.

These potential risks included; Buried waste from heavy metal mining and chemicals such as the pesticide DDTwhich was banned in the early 2000s. Radioactive material has also been dumped in the Arctic – by Russia and the United States – since the start of nuclear tests in the 1950s.

“Sudden thawing of ice rapidly exposes ancient permafrost horizons, releasing compounds and microorganisms that were bound in deeper layers,” Miner and other researchers note in their 2021 paper.

In the research paper, Miner described direct human contamination with ancient pathogens released from permafrost such as “Not likely at this time.”

However, Miner said she was worried about what she calls “Microorganisms of Methuselah” (named after the longest-lived Bible). These are organisms that could transfer the dynamics of ancient and extinct ecosystems to the Arctic today, with unknown consequences.

The resurgence of ancient microorganisms has the potential to alter soil composition and vegetation growth, Miner said, which could further accelerate the effects of climate change.

“We’re really unclear as to how these microbes interact with the modern environment,” he said. “It’s not really an experiment that I think any of us would want to do.”

The best course of action, Miner said, is to try To stop the melt and the broader climate crisis And keep those dangers buried in permafrost forever.

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