Underground Medic 
March 4, 2014
A study published in the Proceedings of the National Academy of Sciences (PNAS)  has revealed that scientists have reactivated a virus found buried in the Siberian permafrost. After thawing it out they found it retained its infectious ability. The French scientists say that the virus poses no danger to either animals or humans.
The virus, Pithovirus sibericum was first discovered 10 years ago. The last time it infected anything was more than 30,000 years ago, but in the laboratory it has sprung to life once again.
Tests show that it attacks amoebas, which are single-celled organisms, but does not infect humans or other animals.
Co-author Dr Chantal Abergel, also from the CNRS, said: “It comes into the cell, multiplies and finally kills the cell. It is able to kill the amoeba – but it won’t infect a human cell.”
However, the researchers believe that other more deadly pathogens could be locked in Siberia’s permafrost. They are concerned that so called global warming and industrial land use such as mining will once again allow these viruses to escape from the ice they are currently locked inside.
Professor Claverie, lead author of the study said in an interview with the BBC:
“It is a recipe for disaster. If you start having industrial explorations, people will start to move around the deep permafrost layers. Through mining and drilling, those old layers will be penetrated, and this is where the danger is coming from.””Ancient strains of the smallpox virus, which was declared eradicated 30 years ago, could pose a risk.””If it is true that these viruses survive in the same way those amoeba viruses survive, then smallpox is not eradicated from the planet – only the surface,” he said.”By going deeper we may reactivate the possibility that smallpox could become again a disease of humans in modern times.”
It is unknown whether all viruses will be able to reactivate after thousands or even millions of years in the deep freeze. These findings may force a rethink on the ease of availability and the use of agents that are considered to be bioterrorism organisms such as smallpox  and anthrax . Conventional thinking is that these pathogens would be stolen from a lab. If they were available from the environment they would be far more difficult to police.