Scientists have revived a giant virus that was buried in Siberian ice for 30,000 years - and it is still infectious, Nature.com reported.
Even though its targets are amoebae, as Earth's ice starts to melt, this could trigger the return of other ancient viruses with potential risks for human health, the researchers said.
According to Nature.com, "The newly thawed virus is the biggest one ever found. At 1.5 micrometers long, it is comparable in size to a small bacterium."
Evolutionary biologists Jean-Michel Claverie and Chantal Abergel, the husband-and-wife team at Aix-Marseille University in France who led the work, named it Pithovirus sibericum, inspired by the Greek word "pithos" for the large container used by the ancient Greeks to store wine and food.
"We're French, so we had to put wine in the story," said Claverie. The results are published in Proceedings of the National Academy of Sciences.
"Once again, this group has opened our eyes to the enormous diversity that exists in giant viruses," said Curtis Suttle, a virologist at the University of British Columbia in Vancouver, Canada, who was not involved in the work.
According to Nature.com, when scientists in Russia resurrected an ancient plant from fruits buried in 30,000-year-old Siberian permafrost two years ago, Claverie and Abergel's team learned about it and were intrigued.
"If it was possible to revive a plant, I wondered if it was possible to revive a virus," said Claverie.
Using permafrost samples provided by the Russian team, they fished for giant viruses by using amoebae - the typical targets of these pathogens - as bait. The amoebae started dying, and the team found giant-virus particles inside them.
Much like the Pandoraviruses, Pithovirus appears as a thick-walled oval with an opening at one end under a microscope. But despite their similar shapes, Abergel notes that "they are totally different viruses."
Claverie and Abergel are concerned that rising global temperatures, along with mining and drilling operations in the Arctic, could thaw out many more ancient viruses that are still infectious and that could conceivably pose a threat to human health, Nature.com reported.
But Suttle points out that people already inhale thousands of viruses every day, and swallow billions whenever they swim in the sea, Nature.com reported.
The idea that melting ice would release harmful viruses, and that those viruses would circulate extensively enough to affect human health, "stretches scientific rationality to the breaking point", he said. "I would be much more concerned about the hundreds of millions of people who will be displaced by rising sea levels."
