A new study by Cornell researcher Raina Plowright and her team sheds light on how changes in bats’ diets due to habitat loss increase the risk of viral spillover to other animals and humans. The study published in the Proceedings of the Royal Society B, provides crucial insights into the connection between diet quality immune response and viral shedding in bats.
Plowright and her team observed that when bats in Australia lost access to their natural food sources, they turned to agricultural lands, consuming lower-quality food. This shift led to increased viral shedding, heightening the risk of virus transmission to horses and, subsequently, humans.
To explore this phenomenon further, the researchers conducted lab experiments with Jamaican fruit bats, feeding them three distinct diets:
•A high-protein diet, similar to their natural fruit intake.
•A low-protein diet, mimicking a diet of mandarins.
•A high-fat diet, resembling the consumption of cocos-palm fruit.
The findings revealed that bats on the low-protein diet shed more virus for a longer duration, while those on the high-fat diet surprisingly shed less virus than even those on the standard diet. However the high-fat diet’s potential benefits remain uncertain as increased foraging behavior might offset the reduced viral shedding by increasing exposure risk.
The study found that dietary changes altered gut metabolites, affecting the bats’ immune response. A key amino acid, citrulline, appeared to boost immune function in bats on the high-fat diet. Researchers are now conducting follow-up studies to manipulate citrulline levels and further analyze its effect on viral shedding.
Plowright emphasized the broader implications of these findings, warning of the growing risks of habitat destruction, climate change, and increasing human-wildlife interactions. She highlighted that bats are known carriers of deadly viruses like Nipah, Hendra, Ebola, and coronaviruses and disrupting their ecosystems intensifies the risk of future outbreaks.
The research underscores the urgent need to preserve and restore natural habitats to reduce human exposure to emerging viruses. Plowright cautioned that the next pandemic could be far deadlier than COVID-19 with some known viruses exhibiting fatality rates exceeding 50-70%.
Plowright said “We are actively dismantling our ability to detect and respond to the next pandemic even as we accelerate our expansion into the natural world disrupting ecosystems displacing wildlife and increasing our exposure to new viruses”.
She stressed the importance of proactive measures, including habitat conservation and ecosystem restoration, to mitigate the risks of viral spillover and prevent the next global health crisis.
