Why bats carry viruses that have higher fatality rates in humans than those from other mammals

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 PLOS Biology, 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. 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 a mathematical model to show how a virus optimizes its chances of survival (by spreading from host to host before a host dies) 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 viruses in bats. And that, the researchers point out, is why the same virus would be more deadly in humans – we have a lower tolerance for inflammation. A lower tolerance, they note, leads to more grave symptoms, such as lungs that are no longer able to process enough air.

Zdroj obrázku: Wikimedia Commons, Fritz Geller-Grimm, CC BY-SA 2.5.