Global warming could cause a ‘viral spillover’ from the Arctic, where viruses, preserved in ice, could be released, a study has found. Viruses need a host to replicate and spread, possibly lacking immunity.
Canadian scientists investigated whether climate change could favor such a scenario in the Arctic environment of Lake Hazen. It is the largest lake located beyond the Arctic Circle. They took samples from the bed of a river that feeds it when the ice melts during the summer, as well as from the bottom of the lake.
“This allowed us to determine which viruses were in a given environment, and which potential hosts were also there”, explained to AFP Stéphane Aris-Brosou, associate professor in the department of biology of the university. Ottawa, who oversaw the study released Wednesday.
The team then set out to find out how susceptible the viruses were to switching hosts, looking at the equivalent of their respective family trees.
Arrival of new guests
‘We sought to measure how well these trees [généalogiques, ndlr] were similar,” explained Audrée Lemieux, from the University of Montreal, first author of the study. Similar genealogies suggest the virus evolved with its host, while differences indicate it may have switched hosts. And if he’s done it at least once, he’s likely to do it again.
The analyzes showed large differences in the family trees of the viruses and their hosts in the 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 acceleration of the melting of the glaciers feeding the lake has also increased the quantity of sediments which are transported there. “It will put hosts and viruses in contact that would not normally be,” said Audrée Lemieux.
The authors of the study, published in the Royal Society’s biological research journal, ‘Proceedings B’, were careful to make it clear that they do not foresee a viral spillover or a pandemic.
‘The probability of dramatic events remains very low’, according to Audrée Lemieux. But according to the researchers, the risk could increase with continued global warming, as new hosts may venture into previously inhospitable regions.
/ATS