Our world is plagued by thousands of different bacterial and viral pathogens each year. From polio to the swine flu, and antibiotic-resistant bacteria to human immunodeficiency virus (HIV). With so many pathogens to worry about in our time, it’s easy to forget that deep inside Siberia’s cold earth, there are ancient pathogens waiting to be released. Well, one of them — a giant one at that — was just released and brought back to life, thanks to a group of French scientists.
Researchers found the virus, called Pithovirus sibericum (pictured here), 30 meters below the surface of Siberian permafrost where it had laid dormant for over 30,000 years. Measuring 1.5 micrometers in length, it’s the biggest virus found so far that is part of a class of other giant viruses first discovered 10 years ago, the BBC reported. In their study, which is published in the Proceedings of the National Academy of Sciences, researchers describe the virus.
Upon thawing the virus, they found that it had retained its ability to be infectious. “This is the first time we’ve seen a virus that’s still infectious after this length of time,” Professor Jean-Michel Claverie, an author of the study from the National Centre of Scientific Research (CNRS) in France, told the BBC. Fortunately, the virus doesn’t infect humans or animals, and instead prefers to attack amoebas — single-celled organisms.
Excavating the virus from the deep Siberian ground highlights other risks that may soon present themselves. Although the Pithovirus may be like a giant cuddly bear to us humans, other viruses more dangerous to human populations may be lurking within, the researchers said. “It is a recipe for disaster,” Claverie told the BBC. Industrial explorations, among other things, could expose the permafrost layers. “Through mining and drilling,” he said, “those old layers will be penetrated and this is where the danger is coming from.” Adding to the problem, climate change has caused the permafrost’s thickness to decrease, resulting in easier accessibility.
For one, ancient strains of smallpox could cause new outbreaks of the disease, which was declared eradicated in 1980. All of this, however, depends on whether other viruses are able to infect after laying dormant for so long, just like the Pithovirus. “That’s the six million dollar question,” Professor Jonathan Ball, a virologist from the University of Nottingham, told the BBC, adding that it’s “pretty astounding” for a virus to remain viable after so much time under freezing temperatures.
To find out about the virulence lurking in the permafrost, the researchers will continue surveying the permafrost for viruses, and sequencing the DNA of any that they find, co-author Dr. Chantal Abergel, who is also from the CNRS, said. “That would be the best way to work out what is dangerous in there.”
Source: Legendre M, Bartoli J, Claverie J, et al. Thirty-thousand-year-old distant relative of giant icosahedral DNA viruses with a pandoravirus morphology. PNAS. 2014.