Scientists will attempt to reanimate a long extinct 30,000-year-old “giant” virus discovered frozen in the permafrost of Siberia. Found buried 30 meters (100 feet) deep in the frozen soil, this could be the second time that the team of researchers will reawaken a prehistoric virus. Called Mollivirus sibericum, this is the fourth prehistoric virus to have been discovered in the last decade and raises questions about what other ones might be locked in the icy tundra.

Giant viruses are those that measure longer than half a micron, or a thousandth of a millimeter, and thus can be observed under a light microscope, unlike other viruses that are far too tiny. Mollivirus sibericum – literally “soft virus from Siberia” – comes in at 0.6 microns, just making it into the giant virus group. Before attempting to revive it, the team of researchers plan on determining if the virus is deadly to animals or humans, though considering all previous examples have turned out to be harmless, the likelihood that this one proves deadly is not very high.

But that doesn’t mean that in the future, other viruses found frozen in the permafrost will be similarly benign. The scientists warn that with climate change melting the ground in northern Siberia at an increasing rate, there is the potential for a more harmful virus being awakened. And in conjunction with an increase in activity in the region in a race for the oil and minerals locked below it, who knows what could be unearthed.

“A few viral particles that are still infectious may be enough, in the presence of a vulnerable host, to revive potentially pathogenic viruses,” explained Jean-Michel Claverie, one of the lead authors of the study published in the Proceedings of the National Academy of Sciences, to AFP. “If we are not careful, and we industrialise these areas without putting safeguards in place, we run the risk of one day waking up viruses such as smallpox that we thought were eradicated.”

The new virus is the second discovered by Claverie and his team, who in 2013 described and, a year later, resurrected Pithovirus sibericum, which was found in the same 30,000-year-old sample of permafrost. What surprised the scientists was not only that they retained their capacity to infect amoeba, but that these prehistoric viruses are much more genetically complex than their smaller modern counterparts. The newly discovered Mollivirus has over 500 genes, and Pithovirus an astonishing 2,500, whereas Influenza A, for example, only has eight.

In safe laboratory conditions, the researchers hope to try and revive the newly discovered virus in order to better understand its origin and mode of evolution. And if it can be easily revived, as before, the authors note that this find "should be of concern in a context of global warming."