Some discoveries researchers may wish they had never made.
One wonders if this isn’t true for the research team that recently found seven ancient types of viruses, frozen in the Siberian permafrost for thousands of years.
These viruses can still infect cells – and are therefore a potential threat to plant, animal and human health,[[[[according to an international research group.
The youngest of the viruses discovered by the researchers was frozen for 27,000 years, while the oldest was hidden under a lake in Yukechi Alas, Russia, for 48,500 years.
The discovery of the old virus thus gives the researchers the honor of having brought back to life the oldest virus ever.
“48,500 years is a world record,” says Jean-Michel Claverie of Aix-Marseille University in France, who carried out the work together with a group of colleagues, up to the New Scientist
His group already has revived two 30,000-year-old viruses from permafrostof which the first of the discoveries was published in 2014.
A huge pandora virus
The 48,500-year-old virus belongs to a species known as the “pandora virus,” a giant virus that infects single-celled organisms, also known as amoebas.
All kinds of viruses that the researchers have revived are actually huge viruses that infect the amoeba.
After the researchers captured the viruses in the permafrost, they crossed the virus types with cultures of amoebas in the lab, which they then examined under a microscope.
There, they could see that there were signs of infection and were then able to establish that the virus was “alive” and capable of infecting.
Therefore, the researchers concluded that if the giant prehistoric viruses are still infectious after being frozen for so long, other types of viruses could also be infectious if they are revived after thousands of years.
It is a risk that increases as climate change continues to thaw the permafrost day by day, explains Jean-Michel Claverie.
“Bacteria and viruses are seeing the light of day every day,” he tells New Scientist, calling it “a real danger” that old viruses could spread again.
“But it’s impossible to quantify this risk,” he adds.
250 million year old bacteria
While 48,500 years is the record for the oldest virus found and revived, scientists have apparently found much older bacteria.
Several research groups say they have revived bacteria that were trapped in sediment, ice or salt crystals, which are up to 250 million years old.
However, it is still unclear whether the bacteria are also that old or whether younger microorganisms may have affected the samples later.
