Siberian permafrost melt may revive ancient viruses, including zombie viruses, with pandemic potential

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19th March 2023 – (Taipei) Dr. Ooi Hean, a pulmonologist and director of China Medical University Hospital’s International Centre, has warned that melting permafrost in Siberia due to rising global temperatures could lead to the resurrection of ancient viruses, including zombie viruses that could cause pandemics.

The thawing of the Arctic’s permafrost due to warmer temperatures could pose a significant threat to human and animal health. A frozen layer of soil beneath the ground, permafrost covers a fifth of the Northern Hemisphere, having underpinned the Arctic tundra and boreal forests of Alaska, Canada and Russia for millennia. It has served as a time capsule, preserving ancient viruses, as well as the mummified remains of extinct animals. However, current day Arctic temperatures are warming up to four times faster than the rest of the planet, causing the top layer of permafrost in the region to weaken.

As permafrost thaws, it releases dormant viruses that have been lying dormant for tens of thousands of years. Experts warn that while the risks of a pandemic being unleashed by a disease from the distant past are low, they are under-appreciated. These viruses could potentially endanger animal and human health. Furthermore, the thawing permafrost may also release chemical and radioactive waste from the Cold War era, which could harm wildlife and disrupt ecosystems.

According to Ooi, as the frozen ground disappears, modern humans may come into contact with a range of viruses that they have never encountered before. Researchers in Europe have already discovered thirteen prehistoric viruses that have come back to life after being found in Siberian permafrost. These viruses are known as “zombie viruses” and still possess infectious capabilities.

Jean-Michel Claverie, a distinguished Emeritus professor of medicine and genomics at Aix-Marseille University School of Medicine in Marseille, France, has conducted an extensive study to comprehend the hazards associated with frozen viruses. In his endeavour to identify “zombie viruses,” Claverie examined earth samples obtained from Siberian permafrost to investigate whether any viral particles within are still capable of infection. Claverie focuses on a distinct type of virus, known as giant viruses, that are significantly larger than the average variety and can be viewed through a regular light microscope, rendering them suitable for laboratory work.

Claverie was partly inspired by a group of Russian scientists who, in 2012, revived a wildflower from a 30,000-year-old seed tissue discovered in a squirrel’s burrow. Scientists have since successfully resurrected ancient microscopic animals. In 2014, Claverie succeeded in reviving a virus he and his team extracted from the permafrost, making it infectious for the first time in 30,000 years by introducing it to cultured cells. To ensure safety, Claverie chose to research a virus that could only target single-celled amoebas, not animals or humans. He repeated this feat in 2015, isolating a distinct virus type that also targeted amoebas. In his latest research, published on 18th February in the journal Viruses, Claverie and his team extracted various strains of ancient virus from numerous samples of permafrost collected from seven different locations across Siberia. The oldest virus, dating back almost 48,500 years, was found in a sample of earth taken from an underground lake 16 metres below the surface. This incredible feat was possible due to radiocarbon dating of the soil. The youngest samples, which were also successfully revived, were found in the stomach contents and coat of a woolly mammoth’s remains and were 27,000 years old.

Ooi’s warning comes amid growing concern about the potential for these viruses to cause a future pandemic. While the viruses observed in this study were only capable of infecting parasitic worms, Ooi noted that there are viruses that can infect humans and that other research teams have found viruses and bacteria that can infect humans in permafrost layers.

For example, in 1997, scientists discovered the genetic remnants of the 1918 Spanish flu virus in the corpse of a woman found in frozen ground in Alaska. Similarly, in 2012, scientists confirmed that the genetic remnants of the smallpox virus were still present in the body of a 300-year-old Siberian mummy.

Ooi cautioned that modern humans have never encountered zombie viruses and that the risk of a future pandemic caused by these viruses is not zero. As such, he urged people to be vigilant about the risks posed by these viruses and to treat them as a future threat.

“There’s a lot going on with the permafrost that is of concern, and (it) really shows why it’s super important that we keep as much of the permafrost frozen as possible,” said Kimberley Miner, a climate scientist at the NASA Jet Propulsion Laboratory at the California Institute of Technology in Pasadena, California.The warming Arctic temperatures are a result of climate change, which is caused by greenhouse gas emissions. The situation is further compounded by human activities such as oil and gas exploration, mining and infrastructure development. All of these activities contribute to the release of more greenhouse gases into the atmosphere, exacerbating the problem.