The extinct pathogens that may have thrived in Earth's permafrost may begin another pandemic. The experts reportedly worry about the still unknown threat, "Factor X."

Earth Edging Towards Ancient Threat Factor X?

Throughout our species' existence, trillions of bacteria have come into contact with our immune systems, causing them to evolve. There might be old viruses in the permafrost, though, to which humans are not naturally immune and cannot effectively vaccinate or cure.

Experts are worried that some of those viruses may resurrect, as some are blamed for the extinction of some species, and start "Factor X."

"There is a Factor X that we really don't know very much about," said Birgitta Evengård, a professor in infectious disease at Umeå University in Sweden.

"These ancient viruses [...] may have infected Neanderthal humans or mammoths, causing their extinction," claimed Jean-Michel Claverie, who led the study providing proof of concept about pandoravirus.

According to the US Environmental Protection Agency, average permafrost temperatures have been rising at about 0.6 degrees Fahrenheit [minus 17.4 degrees Celsius] per decade over the past 50 years, with the Arctic warming up to four times faster than the rest of the world. Scientists worry that various dangerous diseases that have been dormant in the frozen Earth for decades, centuries, or even millennia will suddenly burst forth as the world warms.

Another study previously revealed the same concern, noting that ancient pathogens trapped in permafrost could start a new pandemic. In 2022, scientists resurrected the oldest virus they had found in Siberian permafrost that was melting. It was one of seven distinct virus species that endured under the permafrost for thousands of years.

The youngest had been preserved for 27,000 years, while the oldest, Pandoravirus yedoma, had been frozen for 48,500 years.

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Possible Virus From Permafrost

Evengård notes that there are many things they still don't know about the permafrost. Claverie added that if amoebe viruses can thrive in permafrost for that long, it's very likely that animal/human infecting pathogens could remain infectious under the same condition.

Claverie said the pathogens down there might include the ever-present anthrax, spread by spore-contaminated places; viruses from now-extinct illnesses like smallpox; and the fast-moving diseases already known to [exist] in the Arctic today, including tularemia, a dangerous bacterial infection, or tick-borne encephalitis.

Evengård added that anthrax may also thrive in permafrost because it has a thick cell wall. Thus, it can survive hundreds of years of hibernation and eventually return to life.

Kimberley Miner, a professor at the Climate Change Institute and a climate scientist at NASA's Jet Propulsion Lab in California, said several strategies allow viruses to survive in permafrost, such as repairing their lipid membranes and DNA. This is true for various microbes known as extremophiles, organisms that can withstand high temperatures and pressures, such as the permafrost's cold and pressure.

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Check out more news and information on Permafrost in Science Times.