According to study published on Wednesday, a warmer climate could bring viruses in the Arctic into contact with new ecosystems and hosts, raising the danger of “viral spillover.” Viruses require hosts such as humans, animals, plants, and fungi in order to replicate and propagate, but occasionally they can leap to a new host that lacks immunity, as was the case during the COVID-19 epidemic.
By analyzing samples from Lake Hazen’s arctic terrain, Canadian scientists wished to determine how climate change would increase the danger of spillover.
It is the largest lake totally north of the Arctic Circle and “was absolutely unlike any other location I’ve been,” researcher Graham Colby, who is currently a medical student at the University of Toronto, told AFP.
This handout image captured on May 29, 2017 and made available on October 17, 2022 by Graham Colby depicts researchers drilling holes to gather silt from Lake Hazen in Nunavut in order to explore how climate change may raise the likelihood of “viral spillover.” GRAHAM COLBY/Graham COLBY/AFP sourced through Getty Images
The team sampled soil that becomes a riverbed for melted glacier water in the summer, as well as the lakebed itself, which required clearing snow and drilling through two meters of ice in May.
They used ropes and a snowmobile to raise lake sand through nearly 300 meters of water, and then sequenced samples for DNA and RNA, the genetic blueprints and life’s messengers.
Stephane Aris-Brosou, an associate professor in the biology department at the University of Ottawa and the study’s leader, stated, “This allowed us to determine which viruses are prevalent in a given environment and which prospective hosts are also present.”
But in order to determine how likely they were to jump hosts, the team had to investigate the equivalent of the family tree of each virus and host.
Audree Lemieux, the study’s first author, stated, “Essentially, we attempted to quantify the similarity between these trees.”
Similar genealogies indicate that a virus has co-evolved with its host, whereas discrepancies indicate spillover.
And if a virus has once transferred between hosts, it is more likely to do so again.
“Should climate change also move the range of possible viral vectors and reservoirs northwards, the High Arctic could provide fertile ground for new pandemics,” the researchers wrote in Proceedings B, the biological science publication of the Royal Society.
It is quite unexpected
According to Aris-Brossou, the research revealed considerable disparities between viruses and hosts in the lakebed, “which is directly related to the danger of spillover.”
The researchers hypothesize that this is because water erodes the topsoil, destroying organisms and reducing contacts between viruses and possible new hosts in riverbeds.
These instead wash into the lake, which has undergone “dramatic alteration” in recent years, as increasing water from melting glaciers deposits additional silt, according to the study.
Lemieux stated, “This will bring together hosts and viruses that would not typically interact.”
The authors of the study, which was published in Proceedings of the Royal Society B: Biological Sciences, emphasize that they are neither predicting an actual spillover nor a global epidemic.
“The likelihood of major occurrences remains quite low,” stated Lemieux.
In addition, they caution that additional research is required to determine the size of the difference between viruses and hosts required to cause a severe danger of spillover.
“Disentangling this risk from real spillovers and pandemics will be a crucial endeavor to undertake in conjunction with surveillance activities in order to limit the impact of spillovers on the economy and health-related elements of human life or on other species,” the researchers stated.
They think that if new potential hosts move into previously inhospitable places, global warming could boost hazards even further.
“It may be everything from ticks and mosquitoes to particular animals and even bacteria and viruses,” Lemieux explained.
“It is quite unexpected… and the effect of spillover itself can range from benign to a full-blown epidemic.”
The team desires additional investigation and surveillance in the region to better comprehend the threats.
Lemieux stated, “Obviously, we’ve seen the effects of spillover over the past two years.”