Researchers have isolated viable microbes from melting permafrost after tens of thousands of years. But don't worry; they infect only amoebas.
Under the icy soil of the Arctic is a frozen soup of bacteria, fungi, and viruses.
Some of these microorganisms haven’t interacted with a cell since long before the ancient Egyptians constructed the Pyramids of Giza, unlike the frozen leftovers in the back of your freezer. But even as the earth continues to heat up due to climate change, these permafrost-locked microbes are starting to defrost. However, may recently defrosted bacteria “wake up” and spread disease? And how much of a risk to public and environmental health might they potentially pose?
In a recent study, published on the preprint repository bioRxiv, an international team of researchers started to explore these concerns. Permafrost-related disease outbreaks are not unusual. According to study published in 2021 in the journal Frontiers in Veterinary Science, anthrax is occasionally contracted by Siberian reindeer herds from bacteria in thawed permafrost, and the problem has also harmed a few local humans.
Seven permafrost samples and two water samples collected from Siberian rivers were used in the new study, which has not been peer-reviewed. From these samples, the researchers recovered 13 newly characterised viruses. Three of the viruses, known as Megavirus mammoth, Pithovirus mammoth, and Pandoravirus mammoth, were discovered inside the petrified wool of a mammoth that was 27,000 years old. An further one was found in the frozen intestines of a long-extinct Siberian wolf.
“The ones we revived are no danger at all; they only infect amoeba,” Jean-Michel Claverie, a computational microbiologist at Aix-Marseille University in France and co-author of the new study, told Live Science in an email. “But their presence and infectivity suggests that ancient viruses infecting animals/humans could still be infectious.”
Because amoebas make suitable model organisms and because there would be little chance of unintentional spillover to lab staff, the researchers concentrated on viruses that infect amoebas.
The authors of the article stated that the amoeba’s billion-year evolutionary separation from humans and other mammals serves as the best potential kind of defence.
There have been very few previous studies of viruses trapped in Arctic permafrost. The team discovered trace evidence of multiple additional species, including ones connected to recognised human illnesses, such as poxviruses and herpesviruses, in addition to the viruses they revived, which, according to the scientists, refutes an earlier theory that permafrost contains few viable bacteria.
However, contemporary vaccines would probably provide some protection if one of these strains would awaken and infect humans. According to the authors, unidentified viruses pose the greatest risk. These microorganisms have the ability to spread quickly through a population lacking in natural immunity, resulting in a pandemic, just like SARS-CoV-2, the pathogen responsible for COVID-19. It would be difficult to develop a vaccine for such a virus since it would need to be researched and understood even while it affected humans.
Parvathy Sukumaran 
