A study in Proceedings of the Royal Society B found that the likelihood of spillovers from viruses frozen in the Arctic for thousands of years and new hosts (animals, plants or fungi) increased with the accumulation of sediments carried by melting water from the ice. An increasingly common condition with cryospheric retraction
The University of Ottawa studied Lake Hazen in the Arctic to determine the likelihood of the next pandemic
(sustainabilityenvironment.com) – There is a “high” probability of spillovers for viruses that have so far been stuck in frozen Arctic soil, as the climate crisis advances the melting of permafrost and perennial ice. The next pandemic will therefore come from the thaw and not from bats or birds. This is suggested by a study by the Canadian University of Ottawa published in Proceedings of the Royal Society B, which analyzed soil and sediments of Lake Hazen, the largest in the world in the Arctic region.
Probability and genetic analysis
The novelty of this work is to have provided an estimate of the probability that thawed viruses can infect wildlife and cause the next pandemic. A complex calculation: while animals have evolved for tens or hundreds of millennia, at the same time viruses have remained unchanged.
“We used DNA and RNA sequencing to reconstruct the virosphere of the lake in sediment and soil, as well as the range of eukaryotic hosts. We then estimated the spillover risk by measuring the congruence between the viral phylogenetic trees and those of eukaryotic hosts,” the authors explain.
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Essentially, genetic analysis of viruses and potential hosts has reconstructed how similar the respective family trees are. Many similarities indicate that the virus and animal have co-evolved, while differences suggest a higher probability of spillover risk. The analysis also covers fungi and plants, which are also potentially susceptible to infection.
What do we know about the next pandemic?
The study did not quantify the number of viruses found, nor if they are unknown nor their actual ability to infect – they will be the targets of forthcoming work. But researchers have established a clear correlation between climate change and spillover probability, which would trigger the next pandemic. The probability is higher in the areas where the melting water flows, a condition that is increasingly common as the climate crisis erodes the cryosphere. Another factor that increases the probability of spillover is the northern expansion of the range of part of the fauna.
It must be said that the impact of a possible spillover has a very high margin of uncertainty.
Just as it is very uncertain which organisms could become new hosts. “It could be anything from ticks to mosquitoes, to certain animals, to bacteria and viruses themselves,” the authors explain. “It is really unpredictable. And the effect of the spillover itself is very unpredictable, it can vary from benign to a real pandemic”.
