According to new data, the next pandemic may not come from bats or birds but from matter in melting ice.
Genetic analysis of soil and lake sediments from Lake Hazen, the world’s largest arctic freshwater lake, suggests that the risk of viral spread — as the virus infects a new host for the first time — may be higher near melting glaciers.
The findings suggest that as global temperatures rise due to climate change, it becomes more likely that viruses and bacteria trapped in glaciers and permafrost could wake up and infect local wildlife, particularly as their range also shifts to the poles.
For example, in 2016 Anthrax outbreak in northern Siberia which killed a child and injured at least seven other people, is attributed to a heat wave that melted the permafrost and exposed the carcass of an infected reindeer. Before that, the last outbreak in the area was in 1941.
To better understand the risks posed by frozen viruses, Stéphane Aris-Brosou and colleagues at the University of Ottawa in Canada collected soil and sediment samples from Lake Hazen, near where small, medium and large amounts of meltwater flow from local glaciers.
Next, they sequenced the RNA and DNA in these samples to identify signatures that closely matched those of known viruses, as well as potential animal, plant, or fungal hosts, and ran an algorithm to assess the chance of these viruses infecting non-viral populations. related to living things.
Search published in Proceedings of the Royal Society Bsuggested that the risk of viruses spreading to new hosts was higher at sites close to where large volumes of glacial meltwater flowed—a situation that becomes more likely as the climate warms.
The team did not specify how many previously unknown viruses they had identified – something they plan to do in the coming months – nor did they assess whether these viruses were capable of causing infection.
However, other recent research has suggested that unknown viruses can, and do, hang out in icy ice. For example, last year, researchers at Ohio State University in the United States announce They found genetic material from 33 viruses – 28 of them new – in ice samples taken from them Tibetan plateau In China. Based on their location, the age of the viruses has been estimated to be around 15,000 years.
In 2014, scientists at the French National Center for Scientific Research in Aix-Marseille were able to revive a giant virus They isolated from Siberian permafrost, making it infectious again for the first time in 30,000 years. Study author Jean-Michel Claverie told the BBC at the time that exposing these layers of ice could be a “recipe for disaster”.
However, Aris-Brosou’s team cautioned that predicting higher risk of spread was not the same as predicting actual spread or epidemics. “As long as viruses and ‘bridge vectors’ are not simultaneously present in the environment, the probability of catastrophic events is likely to remain low,” they wrote.
On the other hand, climate change is expected to alter the range of existing species, which could lead to new hosts coming into contact with old viruses or bacteria.
“The only thing we can state with confidence is that as temperatures rise, the risk of fallout in this particular environment increases,” said Aris Brousseau. “Will this lead to epidemics? We absolutely don’t know.”
It is also unclear whether the host switching potential identified in Lake Hazen is unique within the lake sediments. “For all we know, it could be the same as the host switching potential that viruses form from the mud in your local pond,” said Erwin Edwards, director of the Interdisciplinary Center for Environmental Microbiology at Aberystwyth University.
However, “we urgently need to explore the microbial worlds across our planet to understand these risks in context,” he said. Two things are very clear now. First, that the Arctic is rapidly warming and that the greatest risks to humanity are due to its impact on our climate. Second, diseases from elsewhere are finding their way into vulnerable communities and ecosystems in the Arctic.”