Genetic Diversity of Beak and Feather Disease Virus Detected in Psittacine Species in Australia

Abstract

The complete nucleotide (nt) sequence of eight isolates of beak and feather disease virus (BFDV) obtained from a range of psittacine species with psittacine beak and feather disease (PBFD) from throughout Australia were compared with the sequences of two BFDV isolates previously reported from Australia (BFDV-AUS) and America (BFDV-USA), respectively. All isolates had the same basic structure including the position of the open reading frames, the hairpin structure between ORF1 and ORF2, the nonanucleotide motif (TAGTATTAC) therein, the three motifs of Rep protein encoded from ORF1 and involved in rolling circle replication, and the P-loop motif previously described, but the genome size of the eight isolates ranged from 1992 to 2018 nt. Overall nt identity of the isolates compared to BFDV-AUS ranged from 84 to 97%; the variation was due to a combination of point mutations and a number of deletions and insertions ranging from 1 to 17 nt in size detected in both coding and noncoding regions. The identity of the nt sequence of ORF2 compared to BFDV-AUS varied from 80 to 99%, while the identity of the deduced amino acid sequences varied from 73 to 99%. Phylogenetic analysis grouped the isolates into four clusters but there were no apparent regional differences or differences related to the psittacine species of origin. While seven ORFs with the potential to encode proteins greater than 8.7 kDa were detected in the BFDV-AUS isolate described previously, only three of these ORFs were detected in all 10 BFDV isolates for which sequence data were available. The three ORFs were ORF1 that presumably encodes the Rep protein, ORF2 presumably the major capsid protein, and the ORF previously designated ORF5. The ORF5 was of two size classes in different isolates, 303 and 474 nt, and only the first 303 nt of the viruses with an ORF of 474 nt were common to the other isolates.

Molecular analysis and associated pathology of beak and feather disease virus isolated in Italy from young Congo African grey parrots (Psittacus erithacus) with an “atypical peracute form” of the disease

“…We observed that the viral sequences of strains that produce the peracute illness clustered closely with the strains responsible for the chronic disease, thus suggesting the absence of a specific BFDV genetic variant accountable for a specific form of PBFD, as formerly hypothesized (Ypelaar et al, 1999;Bassami et al, 2001;Heath et al, 2004;Raue et al, 2004;Hughes & Piontkivska, 2008). On the basis of this observation, we have hypothesized that the clinical and pathological differences between aPF and CF of the disease could be strictly related to the age and host immune system status, rather than genomic differences between viral strains.…”

Comparitive sensitivity of polymerase chain reaction diagnosis of psittacine beak and feather disease on feather samples, cloacal swabs and blood from budgerigars (Melopsittacus undulates, Shaw 18005)

“…The clustering among these viruses indicates a possible association between the viruses and their host species (Bassami et al, 2001;Ritchie et al, 2003).…”

“…Virus detection in live birds can be achieved by haemagglutination using erythrocytes from goffin cockatoos, guinea pigs or galahs (Ritchie et al, 1991;Raidal et al, 1993). The determination of the complete nucleotide sequence of BFDV was the basis for establishment of molecular detection methods, especially polymerase chain reaction (PCR) (Ritchie et al, 1989;Bassami et al, 1998Bassami et al, , 2001. Ypelaar et al (1999) tested several primer combinations that hybridized with various regions of the genome.…”

Phylogenetic analysis of beak and feather disease virus across a host ring-species complex

“…Accordingly, it is considered a significant conservation threat and has been implicated in parrot declines in Australia and globally (27)(28)(29)(30). BFDV possesses a single-stranded DNA genome of ∼2,000 nucleotides (31). Like most small single-stranded DNA and RNA viruses, BFDV shows high levels of genetic variation and recombination (27,32,33), and evolves rapidly in novel conditions (34), with multiple variant infections present in individual animals (29).…”