Pteropus rufus, the Malagasy Flying Fox, in flight over Madagascar. Credit: Michael McGuire
A small team of biologists and evolutionists from the University of Chicago, York University, the University of California, Berkeley, and the University of Exeter reports why bats carry viruses that cause higher fatality rates when jumping to humans than those that come from any other mammal. In their study, reported on the open-access site, the group used data from past research efforts to model the growth of viruses within bat populations as well as their spread to other animals.
Prior research has shown that when a virus jumps from bats to humans, the results can be deadlier for humans than when viruses jump from other mammals. The reason has been a matter of debate. In this new effort, the team used data from prior research efforts, along with mathematics and modeling, to show that it is due to an innate tolerance for inflammation in bats, which, the researchers suggest, arose with their ability to fly.
To come to this conclusion, the research team first obtained data from other studies about the impact of several viruses on the immune systems of bats that had also jumped to humans. They then used that data in ato show how a virus optimizes its chances of survival by balancing transmission gains with degree of virulence.
They found that a key feature of bat physiology—its ability to fly—was related to its tolerance for inflammation. This was pertinent because it made the bat more tolerant of viruses when infected. That allowed for a high growth rate of