A new study led by Cornell University researchers warns that habitat loss and changes in bat diets can significantly increase the spread of viruses, potentially raising the risk of spillover to humans. The findings provide further evidence that environmental disruption may be fueling future pandemics.
The study, published Feb. 19 in Proceedings of the Royal Society B: Biological Sciences, investigated how diet changes impact viral shedding in bats. The researchers found that when bats were forced to rely on low-protein foods—similar to what they consume after habitat destruction—they shed viruses for a longer duration, increasing the likelihood of transmission.
“In our field studies, we observed a connection between eating poor-quality foods, increased shedding of Hendra virus, and subsequent spillover of the virus into horses,” said lead researcher Raina Plowright, professor of veterinary medicine at Cornell. “We took this question to the laboratory and discovered this stunning result: diet had a profound effect on the animals’ ability to clear a virus.”
Plowright and her colleagues used Jamaican fruit bats to test three diet types: one high in protein, one high in fat, and one low in protein. When infected with a strain of influenza endemic to bats, those on the low-protein diet shed more virus for longer periods. Unexpectedly, bats on the high-fat diet shed less virus than even those on a standard diet.
The study sheds light on a major global concern: the role of bats in carrying and spreading dangerous viruses. Bats are known reservoirs for deadly pathogens, including SARS-CoV-2, SARS-CoV-1, Nipah, Hendra, and Ebola. Scientists warn that continued land development and climate change are intensifying the risk of virus spillover into humans.
“Some of these viruses are incredibly lethal, yet we continue to clear the land, change the climate, and disrupt ecosystems—stressing these animals, removing their food sources, and creating new interfaces between wildlife and humans,” Plowright said. “All of this increases the risk of spillover.”
The research team, composed of behavioral ecologists, immunologists, virologists, and statisticians, also analyzed how diet affects gut metabolites in bats. The amino acid citrulline appeared to play a key role in boosting immune function in bats on the high-fat diet, though further studies are needed to confirm its effects.
Additionally, the researchers are now returning to the field to study whether bats consuming lower-quality diets forage more aggressively and move across larger areas—potentially increasing virus transmission.
“We try as much as possible to have this iterative process, where we spend a lot of time in the field, develop hypotheses, and then test them experimentally,” said co-author Caylee Falvo. “Then, from what we’ve learned in the lab, we go back to the field.”
The study underscores the urgency of protecting natural habitats as a crucial step in preventing future pandemics.
“We’re in an extraordinary situation right now, where we are actively dismantling our ability to detect and respond to the next pandemic, even as we accelerate our expansion into the natural world,” Plowright said. “Many who lived through COVID assume it was the worst a pandemic could be. But the next pandemic could be far deadlier.”
The research was conducted in collaboration with Montana State University, the National Institute of Allergy and Infectious Diseases, Mississippi State University, the University of Missouri, and Colorado State University, with support from the National Science Foundation, the National Institutes of Health, and DARPA.
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