Since the beginning of the 21st century, viruses such as SARS-CoV-1, MERS, Ebola and SARS-CoV-2 have emerged from bat reservoirs to cause extensive disease in human societies. Climate change and expanding civilisations have resulted in more frequent animal-human interactions, increasing the incidence of viral zoonoses and subsequent pandemic risk. Outbreak control has historically relied on reactive measures such as transmission mitigation with concomitant vaccine and therapeutic development and rollout. However, reactive vaccine and antiviral development is time intensive and ill-suited as the primary method for pandemic control, and more effort should be directed at preventing viral zoonoses. The assessment of potential viral spillovers involves monitoring the virome within zoonotic reservoirs and identifying those with human pathogenic ability.
Increased adoption of next-generation sequencing has accelerated viral discovery. Bioinformatics allows increased capability to analyse large datasets and identify novel viruses from diverse hosts. Therefore, viral discovery using wide-scale sequencing and analysis could be used to assess the pathogen pool within wildlife at the human-animal interface. This study focuses on global bat populations to identify mammalian-infecting viruses and thus better understand the viral diversity within this animal reservoir.
We utilised a BLAST-based bioinformatic approach to discover viral sequences in 56 bat species utilising 157 bat RNA-Sequencing datasets. We identified 25 novel viral sequences (>600 nt in length), six of which were full length, from nine different viral families. The Arenaviridae, Hepeviridae and Caliciviridae families all contain known human pathogens and have demonstrated zoonotic potential. A novel Arenaviridae sequence was present in a Dominican Artibeus jamaicensis bat, whilst two Hepeviridae and two Caliciviridae sequences originated from two Chinese Rhinolophus malayanus bats. Four different astro-like viral transcripts were also identified, expanding their known host range from fish and herptiles to mammals.
In summary, we uncovered 25 novel viral sequences in recognised reservoir populations. This progresses our understanding of the bat virome and their zoonotic and pathogenic potential in a step towards preventing pandemics.