Climate change is pushing mammals into new territories and increasing the number of opportunities for viruses to jump from species to species – including humans. If global temperatures continue to rise as predicted, there could be a total of 15,000 new cross-species viral sharing events by 2070, according to New research appeared in the magazine today Nature.
Of the at least 10,000 virus species among mammals capable of infecting humans, most still only circulate among animals in the wild. The concern is that potentially more of these viruses could make the leap to humans trigger a health crisis like the COVID-19 pandemic.
“Ultimately, this work gives us more indisputable evidence that the coming decades will not only get hotter, but sicker.” Gregory Albery, a disease ecologist at Georgetown University and co-lead author of the study, said in a call with reporters.
As global temperatures rise, many species may need to migrate because of changes in the climate to which they are accustomed. Others might find that places that were once inhospitable – maybe they were too cold – are becoming more enticing. They bring pathogens with them on their travels. Essentially, viruses now have more hosts to hitchhike long distances with. This allows viruses to reach places and species that they otherwise would not have been able to access in the past.
“Even now, that process has likely taken place, largely unobserved and beneath the surface, and we need to start looking for it,” Albery said.
When a virus happens from one species to another it is referred to as “overflow” Event. When spillover occurs between an animal and a human, zoonosis can result. The virus that causes COVID-19 is a zoonotic virus, which means it can be transmitted between humans and other animals. It gives proof The novel coronavirus originated in bats. But it probably jumped to at least one other animal before they reach humans.
The authors of the new study examined possible shifts in the geographic ranges of over 3,000 mammal species in a warming world. They also considered how land use might change, for example through deforestation and urban development.
Research shows that in a future of two degrees of global warming above pre-industrial levels, there could be over 300,000 “first encounters” between different animal species. Most of these encounters would likely take place in tropical Asia and Africa. And that could result in 15,000 transmission events, where at least one novel virus jumps from one species to another. Much of the predicted spread of viruses involves bats, which are unique among mammals in their ability to fly from continent to continent.
The researchers are spared how often viruses could then spread to humans. And not every virus that spreads from an animal to a human triggers an epidemic. But Albery noted in the press release that if a virus jumps to a new species, it can create conditions that could help the virus evolve into one that is “particularly well suited or well positioned to jump into to create man”.
Take raccoons, which can thrive in forests, swamps, suburbs, and city centers. If these resourceful raccoons suddenly become susceptible to a new virus, they may be in a much better position to bring that virus to places where humans live. And since the virus has already made a leap from another animal species to a raccoon, the virus has shown a tendency to switch between species.
The new paper suggests these trends are already underway and will pose a problem even under some of the best-case scenarios for future climate change. Became well on our way to exceed this two-degree threshold; the world has already warmed by over a degree.
The COVID-19 pandemic emerged shortly after this research was completed, which the authors say indicates an urgent need to prepare for more spillovers. “We need to take this seriously as a real-time threat,” Georgetown University biologist Colin Carlson, another lead author of the study, said on the conference call. “We must acknowledge that climate change will be the largest upstream driver of disease emergence. And we need to build health systems that are ready for it.”
This includes pairing surveillance of new viruses with observations of how the species’ geographic ranges are shifting, the authors say. It’s part of a larger movement to adopt a concept by the name a healthwhich recognizes that the health of animals, people and the environment are all connected.
https://www.theverge.com/2022/4/28/23044725/climate-change-zoonotic-virus-spillover A warming world gives viruses more chances to hitchhike from species to species