Climate change | Increased risk of new pandemics

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

Posted at 12:00.

Mathieu Perrault

Mathieu Perrault
Press

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

Climate experts often focus, rightly so, on what can be done to minimize climate change, says another co-author, Colin Carlson, also from Georgetown, who is part of the IPCC group. “But in the case of zoonoses — diseases that are transmitted from animals to humans — and pandemics, the focus should instead be on how to respond to the inevitable problem,” Carlson said during a press conference Wednesday. We must ensure better monitoring of zoonoses, strengthen our health systems. »

Bat involvement

Of the more than 3,300 mammalian species studied by researchers, bats are among the most implicated in virus transmission because they fly far and their very strong immune systems allow them to carry many viruses without getting sick. The COVID-19 pandemic likely originated from a bat virus that was transmitted to a wild animal sold in Chinese markets, possibly a pangolin.

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

Study of Nature possible changes in the range of these mammals depending on climate change are modeled. The probability of transmission of the virus from one species to another, associated with genetic similarity between different mammals, was also modeled. “This is a multi-year work,” Carlson said. The number of mammals studied is about half of all species and is therefore relatively representative.

Even the Arctic is not spared

Most of the transmission of the virus from species to species occurs in Asia and Africa due to their rich biodiversity. “But it is possible that there will be many viral crossovers in South America in the future,” Carlson said. The researchers believe that for mysterious reasons this phenomenon does not often occur in South America, but the very high biodiversity present there certainly contributes to this phenomenon. Perhaps we simply do not have enough data for the region. Very little is known about animal viruses in South America. »

The transmission of viruses from one species to another will also create a problem for wildlife. “In the Arctic, the loss of sea ice will facilitate the transmission of viruses between marine mammals. According to Carlson, this could lead to devastation for some populations. We are already receiving reports of mass seal deaths in the Arctic. »

Several journalists asked for specific examples of possible transmission of the virus. But the researchers didn’t want to be more specific. “If 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 will undermine the credibility of science,” Carlson said.

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

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  • 10,000
    Number of virus species capable of infecting mammals

    SOURCE : NATURE

    6%
    Proportion of mammalian species carrying virus present in other species

    SOURCE : NATURE

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