Far fewer bat species carry viruses with high potential to cause disease epidemics in people than is widely assumed, researchers from the University of Oklahoma and Yale write in Communications Biology.
In fact, only certain types—especially those found in coastal South America, Southeast Asia, and equatorial Africa—harbor dangerous pathogens such as SARS-CoV-2, Marburg, and Nipah viruses, they found.
The team used advanced machine learning to identify groups of bat species most likely to host highly virulent and transmissible viruses.
"Characterizing host-virus associations is critical due to the rising frequency of emerging infectious diseases originating from wildlife," they wrote. "Past analyses have evaluated zoonotic risk as binary, but virulence, transmissibility, and death burden can vary dramatically."
Role of human encroachment, habitat destruction
A total of 889 mammal species, including 202 bat species, carried 112 virus species from 23 virus families. The viral families Togaviridae and Flaviviridae contained the risky viruses most likely to be found in bats. Rhinolophidae (horseshoe bats) harbored the most-dangerous viruses, aligning with previous analyses.
We hope our analyses can aid in facilitating conversations highlighting the ways in which human activities, not bats inherently, drive zoonotic viral emergence.
The bat superfamilies Emballonuroidea and Vespertilionoidea, most of which can roost in human-made structures such as houses, may pose a higher risk for viral spillover to people. Identifying the wildlife species most likely to carry these viruses can help target surveillance and conservation efforts, which can be time- and labor-intensive and costly.
Human encroachment and bat habitat disruption can increase zoonotic viral spread by increasing interspecies contact and stressing bats, which may tax their immune systems and boost viral shedding, the authors reported.
Culling bat colonies is not the solution, however, because this can increase viral prevalence in bats and amplify spillover risk. "We hope our analyses can aid in facilitating conversations highlighting the ways in which human activities, not bats inherently, drive zoonotic viral emergence," the researchers wrote.
Indeed, bats benefit ecosystems through, for example, pollination, seed dispersion, and agricultural pest consumption. "If we lost bats, agricultural production would be negatively affected, and so would economies," lead author Caroline Cummings, a doctoral student at the University of Oklahoma, said in a university news release.
