“Zombie” viruses that spent up to 48,500 years frozen in the ground could reawaken as the permafrost melts due to climate change, scientists warn.Noticeably warmer temperatures in the Arctic are already thawing the region’s permafrost, the permanently frozen layer below Earth’s surface.Researchers are now trying to assess how big a risk the bacteria and viruses trapped inside might pose for humans - and they’re carefully reviving some of them in the process.“Fortunately, we can reasonably hope that an epidemic caused by a revived prehistoric pathogenic bacterium could be quickly controlled by the modern antibiotics at our disposal [...] even though bacteria carrying antibiotic-resistance genes appear to be surprisingly prevalent in permafrost,” authors of a study published in February in the journal Viruses wrote.It warned “the situation would be much more disastrous in the case of plant, animal, or human diseases caused by the revival of an ancient unknown virus” for which there would be no specific treatment or vaccine immediately available.The thawing of the permafrost in Siberia has already been linked to anthrax outbreaks in reindeer, as exceptionally hot summers there caused ancient anthrax spores to resurface from animal burial grounds.
In this latest study, French researcher Jean-Michel Claverie and his team reported they had managed to isolate and revive several ancient viruses from the permafrost, including a giant virus strain (Pithovirus) found in a 27,000-year-old permafrost sample containing a lot of mammoth wool.Most of the virus isolates were of the Pandoraviridae family, a family of double-stranded DNA viruses that infect amoebae - very small, simple organisms made of only one cell.“This study confirms