Scientists have revived a giant virus that was buried in Siberian ice for 30,000 years. Surprisingly, the virus is still infectious, although its targets are amoebae. Named Pithovirus sibericum, this newly thawed virus is the largest viral particle ever found, at 1.5 micrometers longs, rivaling small bacterium.
Evolutionary biologist Jean-Michel Claverie and Chantal Abergel lead efforts in studying this giant virus. Under a microscope, Pithovrius appears as a thick-walled oval with an opening at one end. It has a “cork” with a honeycomb structure capping its opening. It copies itself by building replication factories in its host’s cytoplasm rather than by taking over the nucleus. Interestingly, only one-third of its proteins are similar to those of other known viruses. Additionally, its genome is surprisingly small for its size.
The discovery of the virus brings up an interesting concern, however, regarding the effects of global warming on virology. 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 potentially pose as a threat to human health.