More risks as global warming continues

TOKYO (AFP) – A warming climate could cause Arctic viruses to come into contact with new environments and hosts, increasing the risk of “viral spillover”, according to a study published on Wednesday.

Viruses need hosts like humans, animals, plants, or fungi to replicate and spread, and sometimes they can jump to a new one that lacks immunity, as seen during the pandemic of COVID-19.

Scientists in Canada wanted to study how climate change might affect the risk of overflow by examining samples of Lake Hazen’s arctic landscape. It’s the largest lake in the world, north of the Arctic Circle, and “was really like no other place I’ve been,” said University of Toronto researcher and medical student Graham Colby. . AFP.

The team sampled the ground that becomes a river bed for glacier meltwater in the summer, as well as the lake bed itself – which involved clearing snow and drilling through two meters of ice, even in May when the research was conducted. They used ropes and a snowmobile to lift lake sediment through nearly 300 meters of water, and samples were then sequenced for DNA and RNA, genetic blueprints and messengers of life.

“It allowed us to know which viruses are in a given environment and which potential hosts are also present,” said an associate professor in the department of biology at the University of Ottawa, Stéphane Aris-Brosou. But to find out how likely they were to switch hosts, the team had to look at each virus’ equivalent and the host’s family tree.

Researchers drill holes to collect sediment at Lake Hazen in Nunavut. PHOTO: AFP

“Basically what we tried to do was measure how similar these trees are,” said the research’s first author, Audree Lemieux.

Similar genealogies suggest a virus evolved with its host, but differences suggest spillover.

And if a virus has jumped once on hosts, it is more likely to do so again. The analysis revealed pronounced differences between viruses and hosts in the lake bed, “which directly correlates with the risk of spillover,” Aris-Brosou said.

The difference was less marked in riverbeds, which the researchers believe is because water erodes topsoil, killing organisms and limiting interactions between viruses and potential new hosts.

These instead wash into the lake, which has seen a “dramatic change” in recent years, according to the study, as increased water from melting glaciers deposits more sediment.

“It’s going to bring together hosts and viruses that wouldn’t normally come together,” Lemieux said.

The authors of the research, published in the Proceedings of the Royal Society B: Biological Sciences, warn that they do not foresee a real spillover or a pandemic.

“The likelihood of dramatic events remains very low,” Lemieux said.

They also warn that more work is needed to clarify how important the difference between viruses and hosts is in creating a serious spillover risk. But they argued that global warming could further increase the risks if potential new hosts move into previously inhospitable regions.

Teresa H. Sadler