Scientists alarmed after bats' new diet triggers surge in dangerous behavior: 'Had a profound effect'

Researchers at Cornell University took to the lab to confirm surprising findings from an earlier field study of bats: that disrupting these animals' natural habitat and altering their diet affects their risk of spreading disease.

What's happening?

Originally, Cornell researcher Raina Plowright and her team observed bats in Australia, Cornell reported. Habitat destruction removed the bats' access to their traditional diets, so they began looking for food on agricultural land. Researchers found that with this diet change came an increase in the amount of virus shed by the bats, which in turn increased the spread of disease to horses and the risk that it might spill over to humans.

A new study, published in the Proceedings of the Royal Society B: Biological Sciences, used Jamaican fruit bats in a lab setting to measure the impact of diet on viral shedding. The bats were exposed to a strain of influenza that doesn't cause disease in humans and were kept in three groups: "a standard diet (fruit with protein supplement, similar to fruit and proteinaceous pollen) and two suboptimal diets (high sugar but low protein such as oranges; or high fat but low protein such as cocos palm)," according to the study.

"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, but there had been no work on the immunological mechanisms," said Plowright. "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."

Bats eating lower-quality food continued shedding virus for longer, and researchers noted that disruptions in their environment could also lead to more foraging and travel, which would spread the virus over a larger area.

Why is it important if diet affects the flu in bats?

While the specific virus used in this experiment isn't dangerous to humans, bats can act as carriers for a range of illnesses that can cross the species barrier — and the more humans are exposed, the more likely that gets.

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"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. All of this increases the risk of spillover," Plowright said, noting the eventual possibility of a pandemic with a 50% or even 70% fatality rate — much worse than COVID-19. "In the lab, we used a virus that doesn't cause disease in humans, but our findings provide a framework to better understand the pathogens that pose a real threat."

What can I do about disease spread?

The disruption of animal habitats that could lead to an increased spread of disease has many causes, including deforestation, global warming, and natural disasters. The most effective way to address these problems is by voting for pro-climate candidates who will protect our natural resources. You can also look for products that were made without relying on deforestation.

Do you worry about air pollution in and around your home?

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