Global warming may cause ‘viral spillover’ from the Arctic

Viruses that have so far been preserved in snow may interact with new hosts in other environments, according to a study published Wednesday.

Global warming may be a causeVirus leakageViruses from the Arctic, so far preserved in ice, may interact with new hosts in other environments, according to a study published Wednesday.

Viruses require a host (human, animal, plant or alga) to replicate and spread, as shown by the recent Covid-19 pandemic in humans. Canadian scientists investigated whether climate change could favor such a scenario in the Arctic environment of Lake Hassan. Located in the north of Canada, it is the largest lake beyond the Arctic Circle.

Family trees

The researchers took samples from the river bed and lake bottom during summer ice melt. This required drilling through two meters of ice before reaching the bottom of the lake’s icy water, some 300 meters away. Using ropes, a snowmobile lifted up the sediment, sorted for its DNA and RNA, the genetic code and life’s replicator.

This allowed us to determine which viruses were present and which hosts were present in a given environment.“, explained to AFP Stephen Aris-Brousseau, associate professor in the Department of Biology at the University of Ottawa, who oversaw the study. The team then set out to find out how susceptible viruses are to changing hosts by looking at the equivalents of their respective family trees.

Arrival of new guests

We tried to measure how similar these (family) trees are“, explained Audrey Lemieux of the University of Montreal, the first author of the study. Similar genealogies suggest that the virus evolved with its host, while differences indicate that it may have switched hosts. And if it has done it once, it is likely to do it again.

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The analyzes showed large differences in the family trees of viruses and their hosts in sediments extracted from the bottom of the lake. These differences were less pronounced in the bed of the river feeding the lake. The researchers speculate that meltwater from glaciers erodes bed sediments, thereby limiting interactions between viruses and potential hosts. On the other hand, the rate of melting of the glaciers feeding the lake has also increased the amount of sediments transported there.

Very low probability

It does not normally interact with hosts and viruses.“said Audrey Lemieux, co-author of the study published in the Journal of Biological Research of the Royal Society,Actions b“, they were careful to note that they do not predict any viral spillover or an epidemic.”The probability of dramatic events is very low“, according to Audrée Lemieux. But according to the researchers, the risk may increase with continued global warming, as new hosts may enter previously inhospitable areas.

It can be ticks or mosquitoes or other animals, but also bacteria and viruses“, according to Audrée Lemieux. There is an overflowing possibilityTotally unpredictable, and the consequences range from mild to truly epidemic“, she added.

See more – Global Warming: 2022 “Swiss Glacier Melting Breaks Records”

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