Evidence of psittacine beak and feather disease virus spillover into wild critically endangered Orange-bellied Parrots (Neophema chrysogaster).

We report the recent emergence of a novel beak and feather disease virus (BFDV) genotype in the last remaining wild population of the critically endangered Orange-bellied Parrot (Neophema chrysogaster). This virus poses a significant threat to the recovery of the species and potentially its survival in the wild. We used PCR to detect BFDV in the blood of three psittacine beak and feather disease (PBFD)-affected wild Orange-bellied Parrot fledglings captured as founders for an existing captive breeding recovery program. Complete BFDV genome sequence data from one of these birds demonstrating a 1,993-nucleotide-long read encompass the entire circular genome. Maximum-likelihood (ML) and neighbor-joining (NJ) phylogenetic analysis supported the solitary position of this viral isolate in a genetically isolated branch of BFDV. On Rep gene sequencing, a homologous genotype was present in a second wild orange-bellied parrot and the third bird was infected with a distantly related genotype. These viruses have newly appeared in a population that has been intensively monitored for BFDV for the last 13 yr. The detection of two distinct lineages of BFDV in the remnant wild population of Orange-bellied Parrots, consisting of fewer than 50 birds, suggests a role for other parrot species as a reservoir for infection by spillover into this critically endangered species. The potential for such a scenario to contribute to the extinction of a remnant wild animal population is supported by epidemiologic theory.