Under the trend of warming climate, many animal species are being driven to new environments, a phenomenon that may pose a new threat to the health of human beings around the world.
A new study published in nature, a top academic journal, points out that these animal species forced into new environments are accompanied by their parasites and pathogens. The research team proposes that potential new exposures between different species, driven by climate change, are expected to double over the next 50 years, increasing the risk of viruses crossing between species and eventually infecting humans.
The study predicts that by 2070, the virus will migrate to at least 15,000 new animal species. These increased opportunities for virus sharing could increase the risk of emerging new infectious diseases that jump from animals to humans over the next 50 years, particularly in Africa and Asia.
The study highlights the need to combine virus monitoring with changes in species distribution due to climate change, especially in the tropics. These areas are the cradles of most infectious diseases that can be transmitted from animals to humans.
The paper points out that the geographical migration of such animal species may facilitate the exchange of viruses between previously unrelated species, and may promote the "spillover" of zoonotic diseases, that is, the spread of pathogens from wild animals to humans.
Few previous studies have assessed how global changes affect potential future hotspots of virus sharing and emerging diseases. In the latest study, Colin Carlson, a postdoc in Georgetown University's Department of Biology, and colleagues looked at how the geographic range of 3,870 species of mammals could change under different climate change scenarios by 2070.
Carlson is a young scientist, 26 years old. He was hailed as a "child prodigy" and was awarded the Harry S. Truman Scholarship at the age of 14. He is a global change biologist who studies the relationship between global climate change, biodiversity loss and emerging infectious diseases. Carlson is also an advocate for open, collaborative science, developing open source software in addition to peer review work in the fields of ecology, epidemiology, and global health.
In the study, Carlson and colleagues used a model of shared patterns of mammalian viruses to predict the chances of future cross-species virus transmission between 3139 species of animals. The results show that under the scenario of 2°C of climate warming, it is expected that the reorganization of mammal distribution driven by climate change in 2070 will lead to at least 15,000 new interracial virus sharing events.
"We've probably adapted to these changes." We don't pay close attention to them, they make pandemic risk a problem for everyone. Carlson said the study makes it clear that in every simulation they do, climate change is creating countless hotspots of zoonotic risk in the future and now.
The figures, Carlson said, are still based on the assumption that humanity will comply with the Paris Climate Agreement as much as possible and limit global warming to 2 degrees Celsius by the end of the century. And their predictions don't yet include the additional possibility of birds and marine mammals transmitting the virus between animals and humans.
The study also mentions that new exposures between mammalian species are likely to occur anywhere in the world, but will be concentrated in areas with high population densities in tropical Africa and Southeast Asia. But they added that even the coldest climate regions on Earth will see new species touching and sharing bacteria. For example, some species will be forced to move to higher elevations in response to rising temperatures, gathering in mountainous and high lands, in contact with each other.
The study predicts that these new virus sharing events are primarily driven by bats, which may carry viruses that are easily transmitted to humans.
The team cautions that warming is already happening, and that hot spots for climate-driven species proliferation and virus evolution may already be in transition. This result suggests that climate change has the potential to be a major driver of cross-species virus transmission, which could increase the risk of transmission of infectious diseases to humans.
Amesh Adalja, a senior scholar and infectious disease specialist at the Johns Hopkins Center for Health and Safety, said, "When it comes to the impact of climate on infectious diseases, it's crucial to recognize that models don't easily capture many of the complexities. She wasn't involved in the study, but she cautioned that "the relationship isn't always linear, and some climate change may increase the risk of some infectious diseases, while also potentially reducing the risk of others." ”
Overall, the study highlights that targeted surveillance of future hotspots may help identify infectious diseases that jump between species.
"When we talk about surveillance as a solution, we've known it in the last two years because we had a pandemic, but we didn't stop the coronavirus from coming out, and we need to redouble our efforts to monitor animals and prevent the outbreak from spreading to humans," Carlson said. ”
Thesis link: https://www.nature.com/articles/s41586-022-04788-w