Warming climate may raise risk of Arctic ‘virus spillover’
A warming climate could look out viruses in the Arctic to new environments and hosts increasing the risk of viral spillover, according to newly published research.
Viruses need a host such as a human, animal, plant or fungus to replicate and spread, and sometimes they jump to a new host that lacks immunity, as has happened with the COVID-19 pandemic.
Scientists in Canada hope to study how climate change affects spillover risk by examining samples from Husson Lake’s Arctic landscape.
It is the world’s largest lake, completely north of the Arctic Circle, really unlike any other place I’ve been, researcher Graham Colby, now a University of Toronto medical student, told AFP.
The team sampled the soil that became the bed of the glacier’s melt, as well as the lake bed itself, during the northern summer, which required clearing snow and drilling through two meters of ice, even in May spring in Canada for the study.
Using ropes and snowmobiles, they lifted lake sediment into nearly 300 meters (980 feet) of water, then sequenced the DNA and RNA of the samples, which are the genetic blueprints and messengers of life.
This allows us to know which viruses are present in a given environment, and which potential hosts are also present, said Stephane Aris-Brosou, an associate professor .
But to find out how likely they were to skip the host, the team needed to examine the equivalent of each virus and host’s family tree.
Basically, what we’re trying to do is measure how similar these trees are,said Audree Lemieux, lead author of the study.
Similar lineages suggest that viruses evolved together with their hosts, but differences suggest spillovers.
And, if a virus has jumped a host before, it’s more likely to jump again.
very unpredictable
The analysis found significant differences between viruses and hosts in the lake bed, which directly correlates to spillover risk, Aris-Brosou said.
The differences were less pronounced in river beds, which the researchers speculate is because the water erodes the topsoil, removing organisms and limiting interactions between viruses and potential new hosts.
The lake has undergone dramatic changes in recent years as water from melting glaciers deposits more sediment, which is instead washed into the lake, the study said.
This will bring together hosts and viruses that don’t normally meet, Lemieux said.
The authors of the study, published in the journal Proceedings of the Royal Society B: Biological Sciences, caution that they predicted neither actual spillover effects nor a pandemic.
The potential for drama remains low, Lemieux said.
They also caution that more work is needed to elucidate how different viruses and hosts can be to pose a serious risk of spillover.
But they argue that warming weather could further increase the risk if new potential hosts move into previously inhospitable areas.
It could be anything from beat to mosquitoes to certain animals to bacteria and viruses themselves, Lemieux said.
It’s really unpredictable the impact of the spillover itself is very unpredictable, ranging from benign to a true pandemic.
The team hopes to do more research and monitoring in the area to understand the risks.
Clearly, we’ve seen the effects of spillovers over the past two years, Lemieux said
Scientists find how air pollution causes lung cancer
Scientists say they have identified the mechanism by which air pollution triggers lung cancer in non-smokers, a finding that one expert called an important step for science and society.
The study illustrates the health risks posed by tiny particles from burning fossil fuels, prompting calls for more urgent action on climate change.
It could also pave the way for a new area of cancer prevention, according to Charles Swanton of the Francis Crick Institute in the UK.
Swanton presented the study, which has not yet been published in a peer-reviewed journal, at the European Society for Medical Oncology annual meeting in Paris on Saturday.
Air pollution has long been linked to a higher risk of lung cancer in never-smokers.
But we really don’t know if pollution directly causes lung cancer — or how, Swanton told AFP.
Exposure to carcinogens, such as those found in cigarette smoke or pollution, has traditionally been thought to cause DNA mutations that lead to the development of cancer.
But there’s an inconvenient fact about the model, Swanton says Previous research has shown that DNA mutations can exist without causing cancer and that most environmental carcinogens don’t cause mutations. His research suggests a different model.
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