Most research on the eco-epidemiology of bat-borne viruses is conducted on "one host–one virus" systems. Here, we propose to characterize patterns in the structure of the bat virome at the community level to go beyond the one host-one pathogen paradigm. This project aims to investigate the exchange of viruses between different species and families of bats, and livestock in East Africa by analyzing the structure and dynamic of viral communities in Tanzanian bat communities using a comparative metagenomic approach. We aim at examining the role of host community composition, roost type, and phylogeny in shaping viral diversity as well as identifying patterns in the structure of bat virome. We will also investigate the role of seasonal bat reproduction as a driver of viral community structure and further assess whether certain bat species and/or periods may be at higher risk for pathogen transmission. Besides, the exploration of potential silent circulation of bat-borne viruses in livestock will help to assess if spillovers of bat-borne viruses to other hosts are stochastic events or if the frequency of these events is underestimated. Together, these results will provide important elements for understanding patterns of viral diversity in bat communities and are expected to alter the general view of bat-borne disease ecology.