News — WASHINGTON — As the Earth’s climate continues to warm, researchers predict that wild animals will be forced to move their habitats – likely to areas with high human populations – dramatically increasing the risk of a viral jump in humans that could lead to the next pandemic.
This link between climate change and viral transmission is described by an international research team led by scientists from Georgetown University and is published April 28 in Nature (“Climate change increases the risk of viral transmission between species” DOI 10.1038/s41586-022-04788-w).
In their study, the scientists conducted the first comprehensive assessment of how climate change will restructure the global mammalian virome. The work focuses on changes in geographic range – the journeys species will take following their habitats into new areas. As they encounter other mammals for the first time, the study projects that they will share thousands of viruses.
They say these changes provide greater opportunities for viruses like Ebola or coronaviruses to emerge in new areas, making them harder to track, and in new types of animals, allowing viruses to more easily jump across a species “stepping stone” to humans.
“The closest analogy is actually the risks we see in the wildlife trade,” says study lead author Colin Carlson, PhD, assistant research professor at the Center for Global Health Science and Security. from Georgetown University Medical Center. “We worry about markets because putting unhealthy animals together in unnatural combinations creates opportunities for this stepwise emergence process – like how SARS jumped from bats to civet cats and then from civets to humans. But markets are no longer special; in a changing climate, this kind of process will be the reality in nature everywhere.
It is concerning that animal habitats are moving disproportionately to the same places as human settlements, creating new hotspots of overflow risk. Much of this process may already be underway in today’s 1.2 degree warming world, and efforts to reduce greenhouse gas emissions may not prevent these events from unfolding.
Another important finding is the impact that rising temperatures will have on bats, which account for the majority of new virus shares. Their ability to fly will allow them to travel long distances and share the most viruses. Due to their central role in viral emergence, the greatest impacts are projected in Southeast Asia, a global hotspot for bat diversity.
“At every step,” Carlson said, “our simulations took us by surprise. We’ve spent years retesting these results, with different data and different assumptions, but the models still lead us to these conclusions. It’s a truly amazing example of how we can, in fact, predict the future if we try.
As viruses begin to jump from host species with unprecedented speed, the authors say the impacts on conservation and human health could be staggering.
“This mechanism adds yet another layer to how climate change will threaten human and animal health,” says study co-lead author Gregory Albery, PhD, postdoctoral fellow in the Department of Biology at the College of Arts and Sciences. of Science from Georgetown University.
“It’s unclear exactly how these new viruses might affect the species involved, but it’s likely that many of them will translate into new conservation risks and fuel the emergence of new human epidemics.”
Overall, the study suggests that climate change will become the biggest upstream risk factor for disease emergence, surpassing higher-profile issues like deforestation, wildlife trade and industrial agriculture. The authors say the solution is to couple wildlife disease surveillance with real-time studies of environmental change.
“When a Brazilian free-tailed bat travels all the way to Appalachia, we should be invested in knowing the viruses that accompany it,” Carlson says. “Trying to spot these host jumps in real time is the only way to prevent this process from leading to more spillovers and more pandemics.”
“We are closer than ever to predicting and preventing the next pandemic,” says Carlson. “It’s a big step towards prediction – now we have to start working on the harder half of the problem.”
“The COVID-19 pandemic and the previous spread of SARS, Ebola and Zika show how a virus jumping from animals to humans can have massive effects. To predict their jump to humans, we need to know their spread among other animals,” said Sam Scheiner, program director at the US National Science Foundation (NSF), which funded the research. “This research shows how animal movements and interactions due to global warming could increase the number of viruses jumping between species.”
Other study authors also included collaborators from the University of Connecticut (Cory Merow), Pacific Lutheran University (Evan Eskew), University of Cape Town (Christopher Trisos), and the EcoHealth Alliance (Noam Ross, Kevin Olival).
The authors declare that they have no personal financial interest related to the study.
The research described is supported in part by a grant from the National Science Foundation (NSF) Biology Integration Institutes (BII) (BII 2021909), to the Viral Emergence Research Initiative (Verena). Verena, co-founded by Carlson and Albery, curates the largest open data ecosystem in viral ecology and builds tools to help predict which viruses might infect humans, which animals harbor them, and where they might one day emerge. NSF BII grants support diverse and collaborative teams of researchers investigating questions that span multiple disciplines within and beyond biology.
Additional funding was provided by NSF grant DBI-1639145, the USAID Emerging Pandemic Threats PREDICT program, the Data Valorization Institute, the National Socio-environmental Synthesis Center, and the Georgetown Environment Initiative.
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