climate change | Increased risk of new pandemics

According to a new study, there will be 15,000 crossovers of a virus from one animal species to another by 2070. However, such viral transmissions sometimes result in the virus adapting to humans. This means that more new epidemics or even pandemics are likely to occur.

Posted at 12:00 p.m

Mathieu Perréault

Mathieu Perréault
The press

“It’s a process that’s already underway,” said Georgetown University’s Gregory Albery, one of the co-authors of the study, published in the journal on Thursday. Nature. “This is one of the unavoidable aspects of global warming. It occurs even in the most optimistic scenarios of the Intergovernmental Panel on Climate Change (IPCC). »

Climate experts often and rightly focus on what can be done to mitigate climate change, says another co-author, Colin Carlson, also from Georgetown and part of the IPCC team. “But in the case of zoonoses — diseases that spread from animals to humans — and pandemics, the focus should instead be on how to respond to an unavoidable problem,” Carlson told press during Wednesday’s conference. We need to ensure better surveillance of zoonoses and strengthen our health systems. »

bats involved

Of the more than 3,300 species of mammals studied by researchers, bats are among the most involved in virus transmission because they fly far and their very robust immune systems allow them to transmit many viruses without getting sick. The COVID-19 pandemic likely started with a bat virus transmitted to a wild animal sold in Chinese markets, possibly the pangolin.

Ebola and HIV are other viruses that jumped from one mammal to another before mutating enough to infect humans.

The study of Nature modeled the possible changes in the range of these mammals depending on climate change. The likelihood of a virus passing from one species to another has also been modelled, which relates to genetic similarities between different mammals. “It’s a multi-year job,” Carlson said. The number of mammals studied represents about half of all species and is therefore relatively representative.

The Arctic is not spared either

Most virus transmission from species to species occurs in Asia and Africa due to their rich biodiversity. “But it’s possible there will be a lot of viral crossovers in South America in the future, too,” Carlson said. For mysterious reasons, researchers believe that the phenomenon does not occur often in South America, but the very high biodiversity there certainly lends itself to the phenomenon. Perhaps we simply lack data on the region. Very little is known about South American animal viruses. »

Transmission of viruses from one species to another will also pose a problem for wildlife. “In the Arctic, the loss of sea ice will facilitate virus transmission between marine mammals. It could wipe out some populations, says Carlson. We are already seeing reports of massive seal kills in the Arctic. »

Several journalists asked for specific examples of possible virus transmission. However, the researchers did not want to be more specific. “When I talk about a possible event that will happen when a tiger meets a deer for the first time, but it doesn’t happen, it reduces the credibility of the science,” Carlson said.

The next step, according to Carlson, is to better model the behavior of animals when they come into contact with human populations due to urban expansion and changes in human behavior in the face of climate change. “Our models can be refined to better understand the actual increase in risk. Bird and insect populations must also be included. »

Learn more

  • 10,000
    Number of virus species that can infect mammals

    SOURCE : NATURE

    6%
    Proportion of mammalian species carrying a virus present in another species

    SOURCE : NATURE

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