Body & brain: Camels are likely source of MERS: Most animals tested in Saudi Arabia had signs of infection.

Camels are likely source of merS most animals tested in Saudi arabia had signs of infection 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 discoverers of the oversized microbe. At 1.5 micrometers long, Pithovirus sibericum is 25 to 50 percent longer than the 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, scientists report March 3 in the Proceedings of the National Academy of Sciences. “It’s quite different from the giant viruses already known,” says Eugene Koonin of the National Center for Biotechnology Information in Bethesda,