Prehistoric 'Frankenvirus' Mollivirus sibericum uncovered in Siberian permafrost

 Mollivirus particle at a late assembly stage. Photo: PNAS

One of the researchers, Jean-Michel Claverie, said: "Some viral particles which are still infectious can, in the presence of a receptive host, [lead to] the resurgence of potentially pathogenic viruses in Arctic regions".  He said that climate change is making the Arctic region more accessible for the extraction of mineral and oil resources, which could further expose such viruses.

"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," Professor Claverie told Agence-France Presse.

M. sibericum is the fourth giant virus discovered. The first of the giant viruses, Mimivirus, was found in 2003. The second family of giant viruses, the Pandoravirus, was found in 2013 in a pond in suburban Melbourne, at La Trobe University in Bundoora.