Bats are carriers of some of the most dangerous pathogens for humans and other animals, such as Ebola or the coronavirus. However, an evolution of thousands or even millions of years has made them almost immune, and understanding how this happened can help humans fight future pandemics.
Such is the belief of a group of scientists from the United States, Switzerland, Ireland and Spain, who think that the fact that bats form large groups comprising several species may help illuminate the protection they have against the various diseases they carry.
“Several bat species are tolerant of viruses that are harmful to human health, which means they become reservoirs of diseases,” but they do not develop symptoms, explains Nicole Foley, a researcher at Texas A&M University and the first author of the article published this month in Cell Genomics.
Therefore, in a press release, she states that “understanding how bats evolved viral tolerance can help us learn how humans can better combat emerging diseases.”
The work began with the genetic mapping of bats of the genus Myotis, the second largest group among mammals, with more than 140 species known to date. “They are found almost worldwide and carry a wide diversity of viruses,” says Foley.
In Portugal, for example, it is estimated that there are 27 bat species, nine of which belong to the genus Myotis: Bechstein’s bat (M. bechsteinii), the large mouse-eared bat (M. myotis), the small mouse-eared bat (M. blythii), the southern fringed bat (M. escalerai), the cryptic fringed bat (M. crypticus), the woolly bat (M. emarginatus), the whiskered bat (M. mystacinus), Alcathoe’s whiskered bat (M. alcathoe) and the water bat (M. daubentonii).
The researchers believe that the genetic mapping of bats will help identify the genes that may confer immunity to these flying mammals. Moreover, they think part of the secret may lie in how bats gather in numerous groups, especially during the breeding season.
In these gatherings, which may contain more than one species, “there is a lot of flight activity, greater communication and socialization between species,” notes Foley. “For bats, it’s not much different from going to a nightclub.”
During these events, mating occurs between different species of Myotis, and the scientists have noticed that the genes responsible for the bats’ viral immunity were the genetic material most frequently transmitted during these gatherings.
Therefore, they suggest that this behavior evolved precisely to maximize the spread of antiviral genes among bat populations. Without these gatherings and without hybridization, immunity would likely be restricted to a group of bats, leaving the others exposed to viruses.
And, they write in the article, the places where these gatherings occur should be considered of special interest for conservation “given the unique evolutionary processes” that take place there, i.e., the transmission of viral immunity genes between species, producing hybrids that could help us develop protections against future pandemics.
