Ancient dormant viruses found in permafrost, when revived, can infect amoebae

A team of climatologists from France, Russia and Germany have found that ancient viruses that have been dormant for tens of thousands of years in permafrost can infect modern amoeba when revived. For their study, reported on the free access site Virusthe group collected several specimens of giant permafrost viruses in Siberia and tested them to see if they could still infect modern creatures.

Previous research has shown that permafrost, or frozen ground, is an excellent preservative. Many frozen extinct animal carcasses have been excavated from the permafrost of the northern hemisphere. Previous research has also shown that seeds from dormant plants in permafrost can be induced to sprout once resuscitated. And there is evidence to suggest that viruses and bacteria trapped in permafrost could infect hosts if revived. In this new effort, the researchers tested this theory.

The research team’s effort followed earlier work in 2014 that showed a 30,000-year-old virus could be resurrected and could be infectious. The team continued this effort by reviving a different virus in 2015 and allowing it to infect an amoeba. In this new effort, the team collected several virus specimens from several permafrost sites across Siberia for laboratory testing.

For security reasons, the research team only collects so-called giant viruses and only those that can infect amoebae, not humans or any other creature. By reviving the virus samples, the team discovered that they were still able to infect amoebae. They also discovered, via radiocarbon dating of the permafrost in which they were found, that the viruses had been in a dormant state for 27,000 to 48,500 years.

The researchers suggest their findings hint at a much bigger problem: As the planet warms and permafrost melts, there is a risk that emerging viruses may be able to infect humans. Such a threat is not science fiction, they note – earlier researchers found influenza viruses in a lung sample from a woman who died in Alaska during the 1918 flu pandemic. Another team found a virus linked to smallpox in a mummified woman found in Siberia – she had been there for 300 years.