We are likely to deal with more epidemics as the Earth warms 2022-04-28 16:26:00


A civet cat in a cage.

A civet cat in a cage.
picture: Sakshaye Lalit (AP)

As climate change permanently alters our environment, the world is increasingly opening up to new viruses – with potentially deadly consequences for us humans. a study Thursday’s publication in Nature found that as climate change forces animals to relocate their habitats, they will increasingly communicate with humans and with each other, creating more and more opportunities for deadly viruses to mutate and pass to humans.

“Species will have to act if they are to track climate change,” Colin Carlson, lead author of the study and assistant research professor at Georgetown University Medical Center, said in an email. “When they do, they will come together for the first time and share viruses. Our simulations indicate that in the next half century, this process will completely restructure the global mammalian virus network. This is bad news for human health.”

While there is a large body of research on how climate change can shape epidemics, much of this work focuses on vector-borne diseases — diseases such as malaria, dengue fever, Zika, and yellow fever transmitted to humans by blood-feeding insects such as Ticks and mosquitoes. Hardly any scientific work has looked at how climate affects how viruses are transmitted from wild animals to humans, also known as animal spread. Between 60% and 75% of infectious diseases were initially transmitted from wild animals to humans; According to the newspaper, there are currently thousands of types of viruses capable of infecting humans silently.

The study uses a wealth of data — on viruses and mammalian hosts as well as on climate change and animal habitats — to create a massive map of how the habitats of more than 3,100 mammal species will change over the coming decades. As habitats change, the chances of different species crossing each other and with us increase, and viruses and other pathogens will be along the way. In the 2003 SARS outbreak, for example, research suggests that civet cats, which are eaten in China, may have served as intermediate host for the virus, which helps it pass from bats to humans. And with climate change, bats in particular can come into frequent contact with different types of animals, creating new opportunities for viruses to spread.

“Given their ability to fly, we would expect bats to be able to travel the farthest distance and the fastest, and therefore drive most of this process,” Carlson said.

As a result of this expansion of habitats, new geographic ‘hotspots’ will emerge: places where epidemics and potential epidemics can spawn. For example, traditional Ebola outbreaks clustered in West African countriesBut the study found that by 2070, Ebola outbreaks could be more common in East Africa. “Climate change will create countless hot spots of overlap between increased indirect hazards and human populations,” Carlson said.

We are facing an uphill battle. The world’s temperature has already risen by 1.2°C (2.2°F) above pre-industrial levels; Carlson explained that the process of animals changing their habitats and interacting with other species had already begun. Moreover, mitigating or slowing down the warming may actually exacerbate the problem.

“In extreme warming scenarios, species rapidly lose their habitat and become extinct before they have a chance to share their viruses in new ecosystems,” Carlson said. “Mitigating slows down the speed at which their habitats move, and gives them a more manageable task – thus easier to get to where they’re going, and to share viruses when they get there.”

that it It’s hard to draw a straight line Between any pandemic and climate change, there are a myriad of factors that play a role with each outbreak. But this research shows that staying safe means closely monitoring diseases in wildlife.

“We are committed to a world in which climate change may become the dominant driver of pandemic risk (if not already), even under the best-case scenario for climate change,” Carlson said. “It is urgent that we consider wildlife disease surveillance and outbreak detection as strategies to adapt to climate change.”