鸚鵡Avian polyomavirus及Psittacine beak and feather disease virus感染症之病毒核酸序列分析

Abstract

Avian polyomavirus (APV) and psittacine beak and feather disease virus (PBFDV) are the common viral disease of psittacine birds. APV belongs to genes Avipolyomavirus of the family Papovaviridae, and causes acute fatal disease in young budgerigar with a mortality rate of up to 100%. APV infection is also known as budgerigar fledgling disease (BFD). PBFDV belongs to genes Circovirus of the family Circoviridae. PBFDV affects over 60 species of wild and captive psittacine birds. Clinical signs include chronic and progressive losses of feathers and in some species deformities of the beak and claws. In this study, polymerase chain reaction (PCR) was used to detect nucleic acids of APV and PBFDV for epidemical investigation. The results showed an APV positive rate of 28.8%, PBFDV positive rate of 55.1%, and mixed infections positive rate of 24.6%. By cloning and sequencing, sequences of the PCR products were compared with the sequence obtained from the GeneBank. In PBFDV sequences, the identity of VP1 genome and T antigen coding region genome sequences for Taiwan ranges 94.6-97.3% and 90.1-99.1%, respectively. In PBFDV sequences, the identity of ORF1 and C1 sequences ranges 87.5-97.3% and 86.5-98.4%, respectively. Base on nucleotide and amino acid sequencing analyses, there were variation in the VP1 genome and T antigen coding region genome sequences from that of the APV and samples from the GeneBank. Derived amino acid sequence alignment for PBFDV ORF1 fragments, demonstrates the replication motifs (YCKS) and the nucleotide binding site motif (GPPGCGKS). In PBFDV C1 amino acid sequence have four positions considered as hypervariable.