Can the melting of permafrost due to global warming release viruses and bacteria so far locked in this frozen ground? Could Siberia become a real virus bomb for humanity?
These questions have arisen since researchers succeeded in reactivating a 48,500-year-old “zombie virus” at the end of 2022 locked in permafrost, this permanently frozen ground. Their work was revealed during the pre-publication of their study on the BioRxiv platform (study not reviewed by their peers).
Microbiologist Jean-Marie Alempic, from a CNRS University Aix-Marseille unit, led a team of scientists to Siberia who studied 13 viruses found in permafrost.
Viruses already discovered in 2014 and 2015
“A quarter of the northern hemisphere rests on permanently frozen ground, called permafrost. Due to global warming, the irreversible melting of permafrost releases frozen organic matter for a million years, most of which decays into carbon dioxide and methane, further enhancing the greenhouse effect. Part of this organic matter is also made up of resuscitated cellular microbes (prokaryotes, unicellular eukaryotes) as well as viruses that have remained dormant since prehistoric times,” explains the study, which is not the first of its kind, however.
“Live” viruses were thus discovered in 2014 (the pithovirus) and in 2015 (the mollivirus). “This incorrectly suggests that such events are rare and that ‘zombie viruses’ do not pose a threat to public health,” the scientists say.
For their study Jean-Michel Claverie and his team demonstrated that the zombie virus could still infect unicellular amoebae. “When you put a seed in ground that has been frozen for thousands of years, nothing happens. When you warm the soil, the seed will be able to germinate. It’s the same with a virus, ”explains Professor Claverie.
The Russian Vector laboratory in Novosibirsk
Should we be worried about the reappearance of these viruses? No, for now, because the DNA of viruses and bacteria is degraded. But there are risks, especially with some scientific research of “paleoviruses” directly from the remains of mammoths, woolly rhinos or prehistoric horses preserved in permafrost.
The Vector lab in Novosibirsk “fortunately a BSL4 facility” does this type of research. This laboratory was the key element of the Soviet Biopreparat program intended for biological warfare…
Permafrost areas
More generally, explains the study in conclusion “it is still impossible to estimate how long these viruses could remain infectious once exposed to external conditions (UV light, oxygen, heat) and what is the probability that they will encounter and infect a suitable host in the meantime. But the risk is set to increase in the context of global warming as permafrost melting continues to accelerate and more people populate the Arctic as a result of industrial ventures. »
In 2016 in Siberia, a child died and 23 other people were infected by the appearance of anthrax, also called anthrax, yet disappeared for 75 years in this region. For scientists, the origin most likely dates back to the thawing of a reindeer corpse that died of anthrax several decades ago.
