Trade and conservation implications of new beak and feather disease virus detection in native and introduced parrots

Psittacine beak and feather disease (PBFD), caused by Beak and feather disease virus (BFDV), has spread rapidly around the world, raising concerns for threatened species conservation and biosecurity risks associated with the global pet bird trade. BFDV has been reported in several wild parrot populations, but data is lacking for many taxa and geographical areas with high parrot endemism. This data deficit impedes the development of strategies to mitigate the threats posed by BFDV. We aimed to advance understanding of BFDV distribution in many data deficient areas and determine phylogenetic and biogeographic associations of the virus from five parrot species in Africa, the Indian Ocean islands, Asia and Europe. BFDV was detected in eight countries where it was not known to occur previously, indicating the virus is more widely distributed than currently recognised. We document for the first time the presence of BFDV in wild populations of the highly traded and invasive Psittacula krameri within its native range in Asia and Africa. BFDV was detected among introduced 15 P. krameri on the Indian Ocean islands of Mauritius and the Seychelles, raising concerns for island endemic species in the region. Examination of the phylogenetic relationships between viral sequences, including those detected among wild-sourced parrots seized from illegal trade in Western Africa, revealed likely pathways of transmission between populations. A close degree of phylogenetic relatedness between viral variants from geographically distant populations suggests recent introductions, likely driven by global trade. These findings highlight the need for effective regulation of international trade in live parrots, particularly in regions with high parrot endemism or vulnerable taxa where P. krameri could act as a reservoir host.