Credit: IGS- CNRS/AMU

Scientists have been digging up the remains of ancient plants and animals since time immemorial, but viruses? Jean-Michel Claverie from the Aix-Marseille University School of Medicine has spent the last 20 years searching deep permafrost deposits for preserved ancient viruses. His team recently revived a virus that had been dormant for almost 50,000 years. It might sound like the setup for a post-apocalyptic movie, but Claverie believes it’s in our best interest to know what’s lurking down there.

This isn’t the first time Claverie has awoken an ancient virus. He and his team first managed this in 2014 when they isolated a 30,000-year-old virus from permafrost and infected cultured cells. For safety, Claverie has focused on viruses that only infect single-celled amoebas. The following year, the team did the same with another viral strain. The most recent publication from Claverie’s team details 13 newly isolated viruses, including the oldest ever revived.

Most of the viruses in the study are extremely large by viral standards, some up to two micrometers in length (the same size range as an E. coli bacterium cell). They belong to genera, including Pandoravirus (like the one above), Megavirus, and Pacmanvirus. The oldest organism was Pandoravirus yedoma, which was frozen in permafrost for 48,500 years according to radiocarbon dating of the surrounding soil. The viruses infect even bigger amoeba cells, which the team provided to see if the particles were viable. The study describes how the thawed viruses happily invaded the cultured amoeba cells and, in hours, turned them into factories to produce more ancient viruses.

Claverie tells CNN he worries that people see his research on ancient viruses as a curiosity, but there’s a lesson here. This research focuses on viruses that only infect amoebas rather than plants or animals, but there are undoubtedly viruses preserved in permafrost that would love to set up shop in animal cells — possibly even humans. Claverie’s samples come from Siberian ice cores, many gathered at more than 50 feet (16 meters). However, permafrost is much less permanent in the face of climate change.

As Earth warms, we are losing permafrost across higher latitudes. It’s plausible that viruses preserved in permafrost could become active again without a scientist’s help — a so-called “spillover event.” The new study shows us that a 50,000-year-old virus is still viable. Perhaps even older viruses could awaken as permafrost thaws, which could have unknown consequences for an ecosystem that hasn’t seen these organisms in thousands of years. So, add that to the list of potentially catastrophic outcomes of climate change.

Now read:

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• Viruses Extend Their Lives by Hitching a Ride On Microplastics
• Doctors Use Genetically Engineered Viruses to Fight Drug-Resistant Superbug

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