By Meghan Rosen
After lying dormant in Siberian permafrost for 30,000 years, the largest virus ever discovered is just as deadly as it was when mammoths roamed the Earth.
The virus targets amoebas rather than humans. But thawing, drilling and mining of ancient permafrost could potentially unleash viruses that infect people, say the scientists who discovered the giant virus.
At 1.5 micrometers long, Pithovirus sibericum is 25 to 50 percent longer than previous record holders and about 15 times as long as a particle of HIV. Though shaped like another type of giant virus, P. sibericum has a relatively tiny genome, its discoverers report March 3 in the Proceedings of the National Academy of Sciences.