The thawing of the permafrost due to climate change may expose a vast store of ancient viruses, according to a team of European researchers, who say they have found 13 previously unknown pathogens that had been trapped in the previously frozen ground of Russia’s vast Siberian region.We know that every time we’re going to look for viruses, infectious viruses in permafrost, we are going to find some.” Although the ones they studied were infectious only to amoebas, the researchers said that there was a risk that other viruses trapped in the permafrost for millennia could spread to humans and other animals.Virologists who were not involved in the research said the specter of future pandemics being unleashed from the Siberian steppe ranks low on the list of current public health threats.That means that organisms that have been locked away for thousands of years are now being exposed, as longer periods of defrosting at the soil surface enables objects that had been trapped below to rise upward.An extinct virus “seems like a low risk compared to the large numbers of"