April 1, 2023

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A 48,500-year-old “zombie” virus in a glacier has awakened scientists

Warmer temperatures in the Arctic are thawing permafrost in the region and possibly stirring up viruses that have been dormant for tens of thousands of years. Scientists warn that these viruses can endanger the health of animals and people.

The idea of ​​a pandemic from an ancient disease might sound like something out of a science fiction movie, but scientists warn that the risks, albeit low, are underestimated. Chemical and radioactive waste dating back to cold Warwhich has the potential to harm wildlife and Ecosystem disruptionmay also be released during snowmelt.

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

Covers permafrost one-fifth of the northern hemisphere, having supported the arctic tundra and boreal forests of Alaska, Canada and Russia for thousands of years. acts as a type time capsuleaway from them old viruses – The mummified remains of many extinct animals that scientists have been able to recover and study in recent years, including two young lions and two lions Hairy unicorn.

The reason permafrost is a good storage medium isn’t just because it’s cold — it is an oxygen-free environment, which is not penetrated by light. But the temperatures in the Arctic today are rising to Four times faster from the rest of the planet, which weakens the region’s top layer of permafrost.

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, France, examined soil samples taken from Siberian permafrost to determine if they contained any viral particles. in which it still exists intended. searching for “zombie viruses” – as he calls them – and found some.

(Pithovirus sibericum was isolated from a 30,000-year-old permafrost sample in 2014)

Virus catcher

Claverie studies a specific type of virus that he first discovered in 2003. Known as Giant viruses They are much larger than the standard variety and can be seen with a normal light microscope rather than the more powerful electron microscope – making them a good model for this type of laboratory work.

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The idea of ​​detecting viruses frozen in permafrost was inspired in part by a group of Russian scientists who, in 2012, Revived wild flower From old seed tissue 30,000 years Found in a squirrel hole. Since then, scientists have succeeded in bringing the ancient young animals back to life.

In 2014, a scientist managed to revive a virus he and his team isolated from permafrost, making it infectious for the first time in 30,000 yearsand inserted into cultured cells. For security reasons, he chose to study a virus that he could only target Single-celled amoebaeNot animals or humans.

In 2015 he isolated a different type of virus that also targeted amoebas. In his latest research published in the journal “VirusesClaverie 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 It can infect cultured amoeba cells.

These strains represent the latter Five new virus familiesIn addition to the two I had previously. It was almost the oldest 48,500 years, Based on radiometric dating of the soil, and comes from a soil sample taken from a subterranean lake 16 meters below the surface. The smallest specimens found in the stomach contents and fur of the remains of ancient woolly mammoths 27,000 years.

The fact that viruses that infect amoebas are still infectious after such a long period, Claverie told CNN, indicates a larger problem. He fears that people will not realize the possibility of ancient viruses returning to life Serious threat to public health.

“We consider these viruses that infect amoebae as surrogates for all the other possible viruses that may be present in the permafrost,” he noted.

“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 viruses that infect amoebae are still alive, then there’s no reason why other viruses shouldn’t be alive and able to infect their hosts.”

A previous human injury incident

Traces of viruses and bacteria that can infect humans have been found preserved in the permafrost. A woman’s lung sample extracted in 1997 from the permafrost of a village on Alaska’s Seward Peninsula contains genomic material from the influenza strain responsible for Pandemic of 1918. In 2012, scientists confirmed that 300 years old The mummified remains of a woman buried in Siberia contained the genetic signatures of the virus that causes it pond.

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An outbreak of anthrax in Siberia that infected dozens of people and more than 2,000 reindeer between July and August 2016 was also linked to the thawing of permafrost during very hot summers, allowing ancient breeds of reindeer to die. Bacillus anthracis out of ancient burial sites or animal carcasses.

There needs to be better monitoring of potential pathogen risks in thawing permafrost, said Birgitta Evengaard, professor emeritus in the Department of Clinical Microbiology at Umea University in Sweden.

said the scientist, who is a member of CLINF’s Nordic Center of Excellence, a group that researches the effects Climate change in the spread of infectious diseases In humans and animals in the northern regions.

“If there’s a virus hidden in the permafrost that we haven’t dealt with in thousands of years, it might be Our immune defenses may not be enough“, He said.

Chances of spreading the virus

Scientists do not know how long these viruses can remain infectious when exposed to today’s conditions, or how likely it is that the virus will find a suitable host. Not all viruses are pathogens that cause disease – some are benign or even beneficial to their hosts. And while hosting 3.6 million people, The Arctic is still a sparsely populated place, which makes the risk of human exposure to ancient viruses very small.

However, “the risk is sure to increase in context Global WarmingClavery said, “As the thawing of permafrost will continue to accelerate and more people will live in the Arctic in the wake of industrial projects.”

And he’s not the only one who warned that a region might favor an outbreak – that is, when a virus migrates to a new host and begins to spread. A group of scientists published last year research In soil and lake sediment samples taken from Lake Hazen, a freshwater, located within the Arctic Circle. They sequenced the genetic material in the sediments to identify signatures of the virus and the genomes of potential hosts — plants and animals — in the area.

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Using a computational model analysis, they showed that the risk of viruses passing on to new hosts was higher at sites that were close to places where large amounts of water from glaciers flow into the lake — a scenario that becomes more likely as the climate warms.

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. Scientists must then determine where, when, how fast and how much permafrost is thawing.

Defrosting can be one gradual process Only centimeters per decade, but it can happen faster, as in massive landslides that can suddenly reveal deep, ancient layers of permafrost. This process is also liberating methane and carbon dioxide In the atmosphere – an underestimated driver of climate change.

Miner listed a number of potential hazards currently trapped in the Arctic permafrost in a 2021 study published in Science. The nature of climate change. These potential risks included; buried waste Mining of heavy metals and chemicals such as DDT pesticidewhich was banned in the early 2000s. Radioactive materials It has also been rejected in the Arctic – by Russia and the United States – since nuclear testing began in the 1950s.

In her study, Miner called direct human contamination with ancient pathogens released from permafrost “unlikely at this time.”

However, he said he worries about what he calls it “learning microorganisms” (From the longest-lived written form). 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, Potentially accelerating the effects of climate changethe miner pointed out.

“We don’t know how these microbes will interact with the modern environment,” he said. “I don’t think it’s an experiment any of us want to do,” he added.

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

source: ertnews

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