Discovery and Genomic Characterisation of Novel Papillomaviruses in Australian Wild Birds

Papillomaviruses are small, circular DNA viruses that infect epithelial and mucosal cells, which have co-evolved with their hosts over time. While certain mammalian papillomaviruses-especially those linked to disease-are well studied, there is limited knowledge about papillomaviruses associated with avian species. In this study, we identified two avian papillomaviruses from eye/choana swabs of the sacred kingfisher (<i>Todiramphus sanctus</i>) and the little corella (<i>Cacatua sanguinea</i>), collected in Queensland, Australia. The genomes of these viruses, designated as todiramphus sanctus papillomavirus 1 (TsPV1) and cacatua sanguinea papillomavirus 1 (CsPV1), were found to be 7883 and 7825 base pairs in length, respectively. The TsPV1 and CsPV1 genomes exhibited the highest nucleotide sequence identity (>56%) with papillomavirus genomes previously sequenced from mallards or wild ducks in the United States, followed by those from black-legged kittiwakes and Atlantic puffins (>54%) in Newfoundland, Canada. Both TsPV1 and CsPV1 share approximately a 65% nucleotide sequence identity in the L1 gene with anas platyrhynchos papillomavirus 3 (AplaPV3), indicating that they represent novel avian papillomaviruses. Notably, the two genomes in this study were nearly identical (99.69%), and their L1 proteins shared 100% sequence identity. Phylogenetic analysis positioned TsPV1 and CsPV1 within a clade of avian papillomaviruses associated with closely related avian hosts, including the mallard, African grey parrot, common chaffinch, and Atlantic canary. These findings underscore the importance of further research on studying additional Australian bird species longitudinally, which will help to establish potential disease associations and ecological impacts of previously unrecognised and novel papillomaviruses in Australian wild birds.