LONDON, England, Monday March 10, 2014 – While it lacks the fear factor of the discovery that set the fictional Jurassic Park in motion, there’s still some cause for concern about what lies frozen deep in the Siberian permafrost.
According to a team of French scientists, an ancient virus has “come back to life” after lying dormant for at least 30,000 years.
The virus was found frozen and harmless in a deep layer of the Siberian permafrost. It nevertheless became infectious again after it had thawed.
While researchers say the contagion poses no danger to humans or animals, other more deadly pathogens could be unleashed as the ground becomes exposed.
Professor Jean-Michel Claverie, from the National Centre of Scientific Research (CNRS) at the University of Aix-Marseille in France, said: “This is the first time we’ve seen a virus that’s still infectious after this length of time.”
According to the study, which was published in the Proceedings of the National Academy of Sciences (PNAS), the ancient pathogen was discovered buried 30m (100ft) down in the frozen ground.
Called Pithovirus sibericum, it belongs to a class of giant viruses that were discovered 10 years ago and are all so large that, unlike other viruses, they can be seen under a microscope.
The latest one, measuring 1.5 micrometres in length, is the biggest that has ever been found.
Tests show that it attacks amoebas, which are single-celled organisms, but does not infect humans or other animals.
The researchers nevertheless believe that other more deadly pathogens could be locked in Siberia’s permafrost.
“We are addressing this issue by sequencing the DNA that is present in those layers,” said CNRS’ Dr Chantal Abergel. “This would be the best way to work out what is dangerous in there.”
The researchers say this region is under threat. Since the 1970s, the permafrost has retreated and reduced in thickness, and climate change projections suggest it will decrease further. It has also become more accessible, and is being eyed for its natural resources.
Professor Claverie warns that exposing the deep layers could expose new viral threats.
“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,” he said.
He told BBC News that 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.”
However, it is not yet clear whether all viruses could become active again after being frozen for thousands or even millions of years.
“That’s the six million dollar question,” said Professor Jonathan Ball, a virologist from the University of Nottingham, who was commenting on the research.
“Finding a virus still capable of infecting its host after such a long time is still pretty astounding – but just how long other viruses could remain viable in permafrost is anyone’s guess. It will depend a lot on the actual virus. I doubt they are all as robust as this one.” (BBC)