Pandoravirus: the melting Arctic is releasing ancient germs

Scientists have recently revived several large viruses that had been buried in the frozen Siberian ground (permafrost) for tens of thousands of years. The youngest virus to be revived was a sprightly 27,000 years old.

- Jo Adetunji

And the oldest a Pandoravirus - was around 48,500 years old. This is the oldest virus ever to have been revived. As the world continues to warm, the thawing permafrost is releasing organic matter that has been frozen for millennia, including bacteria and viruses - some that can still reproduce. This latest work was by a group of scientists from France, Germany and Russia; they managed to reanimate 13 viruses with such exotic names as Pandoravirus and Pacmanvirus - drawn from seven samples of Siberian permafrost. Assuming that the samples were not contaminated during extraction (always difficult to guarantee) these would indeed represent viable viruses that had previously only replicated tens of thousands of years ago. This is not the first time that a viable virus has been detected in permafrost samples. Earlier studies have reported the detection of a Pithovirus and a Mollivirus. In their preprint (a study that is yet to be reviewed by other scientists), the authors state that it is "legitimate to ponder the risk of ancient viral particles remaining infectious and getting back into circulation by the thawing of ancient permafrost layers". So what do we know so far about the risk of these so-called "zombie viruses"?