Opportunistic sampling from the near-threatened Alexandrine parakeet uncovers genomes of a novel parvovirus and beak and feather disease virus.

Birds are known to harbour a wide range of pathogenic viruses, including the beak and feather disease virus (BFDV; species, Circovirus parrot), which poses a significant threat to the conservation of endangered avian species. This study reports the genomic identification and characterisation of a novel psittaciform chaphamaparvovirus (PsChPV-6) and BFDV, sequenced from the faecal samples of healthy Alexandrine parakeets (Psittacula eupatria). PsChPV-6 is a linear, single-stranded DNA virus consisting of 4232 nucleotides (nt) with a high A + T content and five predicted open reading frames (ORFs). Key proteins encoded by PsChPV-6, such as the nonstructural protein 1 (NS1) and major capsid protein VP1, demonstrate strong sequence similarities to other avian parvoviruses, with conserved motifs in NS1 crucial for viral replication. The presence of a previously uncharacterised ORF1 region suggests strain-specific viral features that warrant further exploration. BFDV is a circular single-stranded DNA virus in the Circoviridae family and was also identified in the samples. Phylogenetic analysis positioned PsChPV-6 within the Chaphamaparvovirus genus, closely related to parvoviruses from diverse avian species, whereas BFDV was grouped with strains from Australian cockatoos and other nonpsittacine birds, suggesting potential cross-species transmission. These findings contribute to a deeper understanding of the genetic diversity and evolutionary dynamics of these viral pathogens in bird populations, underscoring the importance of ongoing surveillance to evaluate their ecological and veterinary impacts.