Scientists say the ancient virus, frozen in the permafrost of Siberia 48,500 years ago, is the oldest known to date.
It comes from seven types of viruses found in permafrost that have been reanimated after thousands of years of freezing.
The smallest of these has been in a frozen state for 27,000 years, and the oldest, called pandoravirus yedoma, has been in a frozen state for 48,500 years. Although viruses generally do not pose a threat to humans, scientists warn that those that appear with thaws can be “catastrophic” and lead to new epidemics.
“48,500 years is a world record,” said Jean-Michel Claverie, a virologist at Aix-Marseille University in France.
Pandoravirus is a genus of giant viruses that was first discovered in 2013 and is the second largest physical size of all known virus genera after pitoviruses.
This 48,500-year-old specimen was found in permafrost 16 meters below the bottom of Lake Yukichi Alas in Yakutia, Russia.
Professor Claveri and his colleagues have previously resurrected two 30,000-year-old viruses from permafrost, the first of which was reported in 2014. All nine viruses are capable of infecting single-celled organisms known as amoebas, but not plants or animals. However, other frozen viruses can be extremely harmful to plants and animals, including humans.
About 65% of Russia’s territory is classified as permafrost – land that remains permanently frozen even during the summer months.
But as temperatures rise due to global warming, the eternal ice has now begun to melt, releasing things (bacteria, viruses, etc.) that have been frozen for thousands of years.
In recent years, the remains of a woolly rhinoceros, which became extinct about 14,000 years ago, and a 40,000-year-old wolf’s head, which is perfectly preserved as it still has fur, have been discovered.
And even an industry was born based on woolly mammoths, which became extinct about 10,000 years ago, when hunters hunt for unearthed skeletons to extract their tusks and sell them to ivory merchants.
But the discovery of such well-preserved specimens also raised concerns that pathogens that could have been carried by the animals could have been frozen with them and, unlike their hosts, could have survived the freeze-thaw effect.
Professor Claverie last year warned of “very compelling” evidence that “you can revive bacteria from deep permafrost.”
While the pitovirus, which had been frozen about 30,000 years before the experiment, is harmless to humans, Professor Claverie said that viruses frozen for that long could “wake up” and start re-infecting their host.
Scientists disagree on the exact age of the Arctic ice cap, the permafrost surrounding it, and therefore the age of the objects it contains.
But most of the unfrozen finds made so far are from the last ice age, roughly 115,000 to 11,700 years ago.
Professor Claverie and his colleagues stated in their paper that releasing live bacteria or archaea that have been in a state of cryptobiosis in permafrost for millions of years is a “potential public health problem.”
They added that “the situation will be more catastrophic in the event of plant, animal or human diseases caused by the resurgence of an old unknown virus.”
The Arctic is less densely populated than other parts of the world, but Prof Claverie said more people are now heading there to mine resources like gold and diamonds.
Unfortunately, the first step in extracting these resources is to remove the top layers of the permafrost, which exposes people to viruses.
“It is impossible to estimate how long these viruses can remain infectious after exposure to external conditions (ultraviolet light, oxygen, heat) and how likely they are to encounter a suitable host and infect it in this period of time,” the scientists say. the risk should increase with global warming, when permafrost thaw continues to accelerate and more people live in the Arctic as a result of industrialization.”
These nine viruses are described in more detail in a new preliminary document, which has not yet been reviewed, on the bioRxiv server.
Glacier meltwater can transmit pathogens to new hosts, turning parts of the Arctic into “hotbeds for new epidemics.”
Source: Daily Mail