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Climate Change Will Accelerate Viral Spreads, Study Finds


For the next 50 years, climate change will cause thousands of viruses to jump from one mammalian species to another. to work It was published Thursday in Nature. Mixing viruses between animals could increase the risk of spreading to humans and causing a new pandemic, the researchers said.

Scientists have long warned that a warming planet could increase the burden of disease. Malariafor example, it is expected to spread as mosquitoes carrying it expand their range into warming zones. But climate change may herald entirely new diseases, allowing pathogens to pass on to new host species.

“We know that species move, and when they move, they will have a chance to share viruses,” said Colin Carlson, a Georgetown University biologist and co-author of the new study.

To understand what this post will look like, Dr. Carlson and colleagues have built a computer model of potential emissions in a warming world. The researchers started by estimating how thousands of mammals could change their range between now and 2070 as the climate changes.

As temperatures rise, many species are expected to move away from the blazing Equator to find more comfortable habitats. Others may move to the edges of hills and mountains to find cooler altitudes. When different species come into contact for the first time, viruses can infect new hosts.

To understand the likelihood of a successful new infection, the researchers started by creating a database of viruses and mammalian hosts. Some viruses have been found in more than one mammalian species; this means they must have bypassed the type barrier at some point in the past.

using a computational technique called machine learningResearchers have developed a model that can predict whether two host species share a virus.

The researchers found that the more the two species overlapped geographically, the more likely they were to share a virus. This is because hosts are more likely to encounter each other, giving their viruses more opportunities to move between them.

Dr. Carlson and colleagues also showed that closely related species are more likely to share a virus than distant relatives. This is probably because closely related mammals are similar in their biochemistry. A virus adapted to exploit a species is more likely to develop in a relative. It can also evade an immune system that it has already adapted to.

These findings, Dr. It enabled Carlson and colleagues to predict what would happen when mammalian species first come together in a warmer world.

Among the 3,139 species studied, the researchers predicted more than 4,000 instances in which viruses would pass from one species to another. In some cases, just one virus will make the leap. But the models also predicted that multiple viruses carried by one species would spread to the other.

The researchers couldn’t tell exactly which viruses would move between which species. What matters, they argued, is the sheer scale of what is to come.

“When you’re trying to predict the weather, you can’t predict individual raindrops,” said Christopher Trisos, an ecologist at the University of Cape Town and co-author of the new study. “You’re guessing the clouds themselves.”

Rachel Baker, a disease ecologist at Princeton University who was not involved in the study, said the research is an important step forward in understanding how climate change will affect the world’s dangerous viruses. Focusing on previous work single virusinstead of exploring the whole world.

“This is great progress,” he said. “We want to know as soon as possible if there is a link between climate change and the spread of pathogens.”

The researchers found that bats in Southeast Asia would be particularly prone to these transmissions. As of now, many bat species in that area are limited to small ranges and do not come into much contact with each other. But as the planet warms, these bats will quickly fly to suitable climates and encounter new species.

These findings can be particularly ominous for humans. Viruses evolve as they pass into new host species, and could potentially evolve to make them more likely to infect humans. This coronavirus It was caused by Chinese horseshoe bats, which caused SARS in 2002, and then spread to another species – possibly raccoon dogs sold in Chinese animal markets – before infecting humans.

In February, scientists released two studies He claims that Covid emerged through a similar sequence of events that were sold in markets in Wuhan, jumping from bats to wild mammals before infecting humans.

“We believe this is very likely to happen as a result of the interspecies transmission events we predicted,” said Gregory Albery, a disease ecologist at Georgetown University and co-author of the new study.

When researchers looked at where the end of mammals might be in 2070, they found another reason to expect new human outbreaks: They won’t be migrating to wildlife refuges. Dr. “It turns out, these are all the places where we built cities,” Carlson said.

A rare rodent that has little contact with humans today can infect raccoons living comfortably in urban areas with a virus. Dr. “This opens up a whole new way for this virus to spread to humans,” said Albery.

Davis, an epidemiologist at the University of California and not involved in the study, Dr. Christine Johnson warned that such a broad model cannot explain details that could have a major impact on individual viruses. “We need locally-based field studies to understand the effects of climates on species movement and disease transmission risk,” she said.

Climate-induced spreads could begin well before 2070. After all, the planet is already 1.1 degrees Celsius warmer More so than in the 19th century. The researchers found that there was already enough climate change in their computer models to start confounding the viruses, but their models don’t allow them to point to specific viruses making a splash.

Dr. “The amount of warming we had was enough to get it moving,” Carlson said.



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