As the world warms, large stretches of permafrost melt, releasing material that has been trapped in its icy grip for years. This includes a large number of microbes that have lain dormant for hundreds of millennia in some cases.
To study the emerging microbes, scientists have now revived several of these “zombie viruses” from the Siberian permafrost, including one believed to be nearly 50,000 years old, a record age for a frozen virus returning to a state capable of infecting others. organisms.
The team behind the work, led by microbiologist Jean-Marie Alempic of France’s National Center for Scientific Research, says these reanimating viruses are potentially a major threat to public health and further study is needed to assess the danger. that these infectious agents might pose as they wake up from their frozen sleep.
“A quarter of the northern hemisphere is underlain by permanently frozen ground, known as permafrost,” the researchers write in their paper.
“Due to climate warming, irreversible thawing of the permafrost is releasing frozen organic matter for up to a million years, most of which is breaking down into carbon dioxide and methane, further increasing the greenhouse effect.”
The 48,500-year-old amoeba virus is actually one of 13 described in a new study currently in preprint, with nine of them believed to be tens of thousands of years old. The researchers established that each was distinct from all other known viruses in terms of its genome.
While the record virus was found under a lake, other extraction sites included mammoth wool and the intestines of a Siberian wolf, all buried under permafrost. Using cultures of live single-celled amoebas, the team showed that the viruses still had the potential to be infectious pathogens.
We’re also seeing a lot of bacteria being released into the environment as the world warms, but given the antibiotics at our disposal, it could be argued that they would be less of a threat. A new virus, like SARS-CoV-2, could be much more of a problem for public health, especially as the Arctic becomes more populated.
“The situation would be much more disastrous in the case of plant, animal or human diseases caused by the revival of an unknown ancient virus,” the researchers write.
“Therefore, it is legitimate to reflect on the risk of old viral particles remaining infectious and re-circulating through thawing of old permafrost layers.”
This team has a way of diligently digging up viruses in Siberia, with a previous study detailing the discovery of a 30,000-year-old virus. Like the new record holder, it was also a pandoravirus, a giant large enough to be visible under light microscopy.
The revived virus has been given the name Pandoravirus yedoma, which recognizes its size and the type of permafrost soil in which it was found. The researchers believe there are many more viruses to find as well, besides the ones that only target amoebas.
Many of the viruses that will be released as the ice melts will be completely unknown to us, although it remains to be seen how infectious these viruses will be once exposed to light, heat, and oxygen from the outside environment. These are all areas that could be investigated in future studies.
Virologist Eric Delwart of the University of California, San Francisco, agrees that these giant viruses are just the beginning when it comes to exploring what lurks beneath the permafrost. Although Delwart he was not involved in the current study, he has a lot of experience resurrecting viruses from ancient plants.
“If the authors really are isolating live viruses from ancient permafrost, it’s likely that even smaller and simpler mammalian viruses would survive frozen for eons as well,” Delwart told New Scientist.
The research has not yet been peer-reviewed, but is available on bioRxiv.
Source: news.google.com