Bats have been found to be the source of some of the worst viral disease outbreaks in recent years. SARS and Ebola are among those traced back to bats and it is proposed that nCOV-19 (coronavirus) will also have originated from these flying mammals.
21 February 2020
Looking to get a better understanding of the role bats play in spread of deadly viruses, a study from the University of California, Berkeley, US has found that a bat’s immune response to viruses is so ‘fierce’ the virus replicates faster so that when it jumps to mammals with an ‘average’ immune system, such as humans, the virus becomes deadly.
The research team explains that some bats are known to have immune systems that are perpetually primed to mount a defence against viruses. This protects the bat; however, it encourages the virus to reproduce more quickly within a host before defence can be mounted. This, say the researchers, makes bats a ‘unique reservoir of rapidly reproducing and highly transmissible viruses.’ While bats can deal with such viruses, new hosts are not so robust and are quickly overwhelmed.
Cara Brook, postdoctoral Miller Fellow at UC Berkeley and first author of the study said ‘Some bats are able to mount this robust antiviral response, but also balance it with an anti-inflammation response. Our [human] immune system would generate widespread inflammation if attempting this same antiviral strategy. But bats appear uniquely suited to avoiding the threat of immunopathology.’
Researchers noted that disrupting bat habitat appears to stress the animals and makes them shed even more virus in their saliva, urine and faeces infecting other animals. ‘Heightened environmental threats to bats may add to the threat of zoonosis,’ Brook added.
The study has been published in the journal eLife: DOI:10.7554/eLife.48401