Researchers Revive 30,000-Year-Old Giant Virus Frozen in Siberia

A giant virus buried deep in the Siberian permafrost for nearly 30,000 years has been revived. The virus, researchers report, is still infectious, but affects only a certain type of amoebae.

The study on the virus Pithovirus sibericum was conducted by Jean-Michel Claverie, from the National Centre of Scientific Research (CNRS) at the University of Aix-Marseille and colleagues.

P. sibericum has about 500 genes compared to some eight genes found in influenza virus. The "giant" virus can be seen using a light microscope.

Previously, Claverie and colleagues had discovered a new kind of giant viruses, "Pandoravirus." P. sibericum measures 1.5 micrometers long by 0.5 micrometers wide, making it about 30 percent larger than the pandoravirus, the International Business Times reports.

The virus was found in a soil sample collected from coastal tundra in Chukotka near East Siberia Sea, AFP reported. The annual mean temperature in this region is 7.8 degrees Fahrenheit (negative 13.4 Celsius). Radiocarbon dating of the soil sample showed that region had vegetation some 30,000 years ago.

The study shows that viruses locked up deep inside the permafrost can still be infectious. The good news is that the newly-identified virus infects only a certain type of amoebae called Acanthamoeba. However, there could be other viruses that could infect animals or even humans.

"There is now a non-zero probability that the pathogenic microbes that bothered [ancient human populations] could be revived, and most likely infect us as well," Claverie, a bioinformatics researcher at Aix-Marseille University in France, wrote in an email to Livescience. "Those pathogens could be banal bacteria (curable with antibiotics) or resistant bacteria or nasty viruses. If they have been extinct for a long time, then our immune system is no longer prepared to respond to them."

 Jonathan Ball, a virologist from the University of Nottingham, told BBC that there is considerable doubt over the survivability of other viruses in the permafrost.

"But it's the freezing-thawing that poses the problems, because as the ice forms then melts there's a physical damaging effect. If they do survive this, then they need to find a host to infect and they need to find them pretty fast," Ball told BBC.

The study is published in the journal Proceedings of the National Academy of Sciences (PNAS).

Discovery of giant viruses in the recent past has shaken up the evolutionary tree of viruses. The latest find could help researchers understand the evolution of viruses and bacteria.