Scientists have long warned that the release of previously trapped greenhouse gases, such as methane, caused by the permafrost thawing brought on by atmospheric warming will worsen climate change.The potential revival of a virus could infect animals, humans, researchers said. (Representational)

Researchers who revived nearly two dozen viruses, including one that was frozen under a lake more than 48,500 years ago, believe that the thawing of ancient permafrost caused by climate change may present a new threat to people.

Researchers from Europe examined prehistoric samples taken from permafrost in Russia’s Siberia. They discovered that 13 new pathogens, which they resurrected and characterized as “zombie viruses,” continued to be contagious despite spending many ages frozen in the ground.

The thawing of permafrost brought on by atmospheric warming has long been predicted by scientists to worsen climate change by releasing methane and other previously trapped greenhouse gases. Less is known about its impact on dormant pathogens.

Due to the strains they targeted, primarily those able to infect amoeba microbes, the team of researchers from Russia, Germany, and France claimed the biological risk of reanimating the viruses they studied was “totally negligible.” They cautioned that their work can be extrapolated to show the danger is real, saying that the potential revival of a virus that could infect humans or animals is much more problematic.

The researchers published their findings in a preprint article on the preprint server bioRxiv that hasn’t yet undergone peer review. “It is thus likely that ancient permafrost will release these unknown viruses upon thawing,” they wrote. It is currently impossible to predict how long these viruses might remain contagious after being exposed to outdoor conditions or how likely it will be that they will come into contact with and infect a suitable host during that time.