News Feature | March 5, 2014

Thirty Thousand Year-Old Virus Discovered In Newly-Thawed Siberian Permafrost

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By Liisa Vexler

A study published in the Proceedings of the National Academy of Sciences (PNAS) has reported that a 30,000 year-old virus was discovered in the Siberian permafrost.  For 30,000 years, the virus had been buried in over 100 feet of permafrost which has recently melted, revealing the organism. 

The virus has been named Pithovirus sibericum and it is grouped into a class of very large viruses that was discovered a decade ago.  It marks the first time that a virus remained infectious after such a long period of time.  It is also the biggest virus ever discovered.  The virus does not affect humans or animals.  Instead, it infects and kills one-celled organisms called amoebas. 

Viruses are frozen for preservation in laboratories because viruses are capable of remaining viable for many years when stored frozen, so it is not the frigid condition of the permafrost that prevented this organism from reappearing.  The thawing of ice initiates the virus re-emergence.  Once a virus is thawed, there is a very narrow window of time in which that virus can find a suitable host for reproduction. 

A main concern for scientists is that there may be more infectious diseases recurring after long periods of dormancy as the glaciers at the poles continue to melt.  Even smallpox may be dormant under the permafrost.  Other infectious agents that affect humans, animals, and crops may once again see the light of day if melt water continues to erode once-mighty glaciers. Scientists can speed up the process by exploring for resources in the newly-exposed permafrost by mining or drilling.