‘Zombie viruses’ still alive after nearly 50,000 years: study

High temperatures affect permafrost, the frozen layer of soil. Partial thawing of the “permafrost” could affect viruses that have been dormant for thousands of years. That’s the image identified by CNN, quoting the words of Kimberly Miner, a climate scientist who works at NASA’s Jet Propulsion Laboratory at NASA’s Caltech in Pasadena. “There are many things to be concerned about with permafrost, and that really shows why it is so important to preserve as much permafrost as possible,” he says. Permafrost covers one-fifth of the northern hemisphere.

Partial melting of the layer carries risks, explained another scientist, Jean-Michel Clavery, professor emeritus of medicine and genomics at the University of Marseille. The scientist has been examining permafrost samples taken in Siberia for what he calls “zombie viruses”. The scientist studies certain types of viruses that were discovered in 2003 and, due to their size, can be seen through an ordinary microscope. In 2014, a professor — who we read about on CNN — succeeded in “bringing life back” to a virus isolated from permafrost. The virus, through the use of cell cultures, has regained its infectious properties after 30,000 years. To be safe, the experiment included a virus capable of influencing only single-celled organisms, not animals or humans. In 2015, the team repeated their study of a virus that can affect amoebae. In the latest research, published February 18 in the journal Virus, Claverie isolated several strains of the virus from multiple permafrost samples taken from seven different locations across Siberia and showed that each strain could infect cultured amoeba cells. The oldest virus dates back 48,500 years. The smallest of them is “only” 27,000.

“We view these amoeba viruses as surrogates for all the other potential viruses that can be found in permafrost,” Clavery explains to CNN. “We see traces of many, many, many other viruses. We know they’re there. We don’t know for sure if they’re still alive. But our reasoning is that if amoeba viruses are still alive, there’s no reason why other viruses aren’t.” yet alive and capable of infecting its hosts.”

Traces of viruses and bacteria that can infect humans have already been identified in permafrost. In a fragment of a woman’s lung, extracted in 1997 from the permafrost of a village on the Seward Peninsula in Alaska, genomic material was identified for the influenza strain responsible for the 1918 pandemic. And in 2012, scientists confirmed that it contained the remains of a mummified age-old mummy. 300 years of a woman buried in Siberia on traces of the virus that causes smallpox.

Are there real risks associated with melting permafrost? Scientists do not know how long any “frozen” viruses can remain effective once exposed to today’s conditions. The likelihood of the virus encountering a suitable host cannot be established with certainty. Not all viruses are pathogens that can cause disease: some are benign or even beneficial to their hosts. However, Clavery notes, “The risk is set to increase in the context of global warming as the melting of permafrost will continue to accelerate and more people will live in the Arctic as a result of industrial initiatives.”