Fundamental Research Division
The DRF at the CEA assemble approximately 6,000 scientists since January 2016.
Scientific result | Genomics | Biodiversity | Evolution
A new type of giant virus, dubbed “Pithovirus”, was
discovered in the frozen soil of extreme northeast Siberia by
researchers from the CNRS/Aix-Marseille Université, CEA-IRTVS, CEA-IG
and the Russian Academy of Sciences. Buried in the ground, this giant
virus (which is harmless to humans and animals) has survived more than
30,000 years of freezing. Although its size and amphora shape recall
Pandoravirus, the analysis of its genome and its replication mode proves
that Pithovirus is very different. This work brings the number of
distinct families of giant viruses to three.
With the Megaviridae and3/4/2014 Pandoraviridae families, researchers had thought
they indexed the diversity of giant viruses (the only viruses visible by light
microscopy due to a diameter greater than 0.5 microns). These viruses, which
infect amoebas in the genus Acanthamoeba, contain a very large number of genes
as compared to common viruses (viruses like influenza or AIDS contain around ten
genes). The size of their genome is comparable to or exceeds that of many
bacteria.By studying a sample of frozen ground from extreme northeast Siberia
(in the Chukotka Autonomous Region), the researchers were surprised to discover
a new giant virus more than 30,000 years old (contemporary of the Neanderthal
extinction), which they named “Pithovirus sibericum”. Its amphora shape, like
Pandoravirus, first led scientists to believe that it was a new (but certainly
very old) member of this family. However, further analysis of Pithovirus reveals
virtually nothing in common with the previously characterized giant viruses.
This therefore represents a new virus family, bringing the known number of
families of giant viruses to three.
This discovery, coming so soon after that of
Pandoravirus, also suggests that the diversity of viruses with an amphora shape
may be as large as that of the “icosahedral”  viruses, which are among the
most widespread today. This underscores how incomplete our knowledge of
microscopic biodiversity remains, as soon as we explore new
environments.Finally, this study shows that the virus can survive in the
permafrost (a layer of permanently frozen soil in Arctic regions) on a
near-geologic timescale, that is to say over 30,000 years (corresponding to the
This demonstration has important implications for public
health risks related to the exploitation of mineral and energy resources in
circumpolar regions, as global warming makes this increasingly feasible. The
resurgence of viruses that are currently considered eradicated, such as smallpox
(whose replication process is similar to Pithovirus) is no longer the realm of
science fiction. The probability of such a scenario should be assessed
realistically, and a metagenomic study of the permafrost, supported by the
France-Génomique infrastructure (Investissement d’Avenir), is currently
 Having the shape of a polyhedron with 20 sides.
CEA is a French government-funded technological research organisation in four main areas: low-carbon energies, defense and security, information technologies and health technologies. A prominent player in the European Research Area, it is involved in setting up collaborative projects with many partners around the world.