30,000-Year-Old Giant Virus Unearthed From Siberian Permafrost

High Arctic Permafrost
Patterns in permafrost in the High Arctic in September 2005. Scientists have discovered the thawing ground is releasing acid. Brocken Inaglory/used under Creative Commons 3.0

Scientists have discovered a prehistoric giant virus buried under deep layers of Siberian permafrost, which they are reanimating in order to explore how the virus developed some 30,000 years ago.

The virus, called Mollivirus sibericum, is the fourth prehistoric virus found since 2003, AFP reported. The research was published in the journal Proceedings of the National Academy of Sciences. The newly-discovered virus measures 0.6 microns, qualifying it as a giant virus, which is anything above 0.5 microns. By comparison, the human immunodeficiency virus (HIV) is around 0.09-0.12 microns in diameter.

The team is currently working to reanimate the virus, which was discovered in northeastern Russia. The same research team discovered another giant virus (Pithovirus sibericum) in the same location in 2014 and found it to still be infectious in amoebae.

Jean-Michel Claverie, director of the Structural & Genomic Information Lab at Aix-Marseille University and one of the new study's lead authors, says he is concerned that global warming, combined with increased drilling for oil in the arctic and subarctic regions, could raise the possibility that other as-yet-undiscovered viruses are released. Some of these may be dangerous to humans.

"If we can revive viruses at those depths and of that age, the chance is that other viruses will also be able to survive," says Claverie. He mentions smallpox, which was declared extinct in 1980 following a global immunization campaign, as an example of viruses which could be reawakened by the melting ice.

"I'm not saying that deep layers of permafrost are going to thaw tomorrow...but if you start mining for something, you will excavate layers of frozen soil by millions of tons," says Claverie. "If there is something nasty there, it will be released in the atmosphere and [affect] the people who are working there."

As well as releasing ancient viruses back into the ecosystem, climate change could have a number of other negative health effects. The U.S. Environmental Protection Agency (EPA) predicts that global warming may enhance the spread of bacterial diseases; salmonella, for example, reproduces more quickly in warmer conditions. In addition, waterborne parasites could also spread more widely as the chance of flooding increases with rising ocean levels.

At the time of their 2014 discovery, the team raised their concerns about the potential release of human-infecting viruses from permafrost. However, Curtis Suttle, a virologist at the University of British Columbia in Vancouver, who was not involved in the work, told Nature this hypothesis "stretches scientific rationality to the breaking point" and that he would be "much more concerned about the hundreds of millions of people who will be displaced by rising sea levels."