An Update on Eukaryotic Viruses Revived from Ancient Permafrost

• Published in: Viruses
• Main Authors: Jean-Marie Alempic, Audrey Lartigue, Artemiy E. Goncharov, Guido Grosse, Jens Strauss, Alexey N. Tikhonov, Alexander N. Fedorov, Olivier Poirot, Matthieu Legendre, Sébastien Santini, Chantal Abergel, Jean-Michel Claverie
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2023
• Subjects: permafrost; Acanthamoeba; giant virus; Pleistocene; Siberia; Kamchatka; Microbiology; QR1-502; lena river
• Online Access: https://doi.org/10.3390/v15020564; https://doaj.org/article/29ddcb45067f406d8274679402de92ec

One quarter of the Northern hemisphere is underlain by permanently frozen ground, referred to as permafrost. Due to climate warming, irreversibly thawing permafrost is releasing organic matter frozen for up to a million years, most of which decomposes into carbon dioxide and methane, further enhancing the greenhouse effect. Part of this organic matter also consists of revived cellular microbes (prokaryotes, unicellular eukaryotes) as well as viruses that have remained dormant since prehistorical times. While the literature abounds on descriptions of the rich and diverse prokaryotic microbiomes found in permafrost, no additional report about “live” viruses have been published since the two original studies describing pithovirus (in 2014) and mollivirus (in 2015). This wrongly suggests that such occurrences are rare and that “zombie viruses” are not a public health threat. To restore an appreciation closer to reality, we report the preliminary characterizations of 13 new viruses isolated from seven different ancient Siberian permafrost samples, one from the Lena river and one from Kamchatka cryosol. As expected from the host specificity imposed by our protocol, these viruses belong to five different clades infecting Acanthamoeba spp. but not previously revived from permafrost: Pandoravirus, Cedratvirus, Megavirus, and Pacmanvirus, in addition to a new Pithovirus strain.