Pithovirus: a new giant DNA virus found from more than 30,000-year-old sample

A third type of giant DNA virus named Pithovirus was recently isolated from a ＞30,000-year-old permafrost sample in Siberia （Legendre M,et al,2014）.Pithovirus has a larger pandoravirus-like particle with 1.5 μm length and its adenine-thymine-rich genome is about 600 kb,which is surprisingly smaller than Pandoravirus.There is very slight genetic relationship between Pithovirus and Pandoravirus and their replication cycles significantly differ.The groundbreaking discovery of this ancient virus expands our understanding of giant DNA viruses and raises the concern of pathogen reemergence from permafrost regions because of the change of climate or the activity of human.