Characterisation of persistent viral infections in bats

Background The great diversity and geographical distribution of bats means it of no surprise that they are a reservoir and transfer vector for many viruses, which once they have crossed the species barrier can be lethal (Filovirus, Flavivirus, Henipavirus, Lyssavirus). We are interested in looking for persistent or latent infection of bats such as herpesviruses and retroviruses. While these are not emerging infections, they have the potential to reactivate and cause zoonoses. Methods Polymerase chain reactions were performed using DNA/RNA samples extracted from bat brain tissue. Samples were collected from 4 different species of bats that were sent to the UK VLA from a number of UK zoos. Degenerate primer sets were designed to amplify specific groups of persistent and endogenous viruses. Results Preliminary analyses of sequences we have amplified indicates that persistent and/or latent infections do exist within bat species. Comparison of retroviral elements cloned from samples of bat brain tissue show the greatest degree of similarity to known gamma- and deltaretroviruses. Using degenerate primers designed to detect herpesviruses, we observe potential sequence that suggest the minority of bat brains (10%) could be infected with latent virus. However, confirmation of herpesvirus infections needs to be carried out. Conclusions Together these results suggest that bats are no exception to the diversity of endogenised and persistent infections among mammals. Further work will include more detailed characterisation of isolated sequences identified in this work. We also hope to obtain more samples, including immune tissues that, given the viruses’ tropism are more pertinent tissues for picking up certain viral infections