Development of an antigen-capture ELISA for beak and feather disease virus

Psittacine beak and feather disease (PBFD) is characterised by degenerative feather, feather dystrophy, and beak deformity. Sometimes acute forms can lead to fatal cases in nestlings. The worldwide distribution of this disease affects numerous species of parrots with an average prevalence of 40%, including in Taiwan. The pathogen of PBFD is beak and feather disease virus (BFDV), which is a single-stranded circular DNA virus, circovirus. To date, hemagglutination and PCR assays have been routinely used to detect this virus. In this study, both the replication-associated protein (Rep) and the structural capsid protein (Cap) were expressed and then used as antigens for the production of monoclonal antibodies. Conserved epitopes recognised by the anti-Cap and anti-Rep monoclonal antibodies were determined to be NFEDYRI and LSALKKM, respectively. Clinical samples collected from different species of parrots were tested by hemagglutination, PCR, and anti-Cap antigen-capture ELISA assays and the positive rates were the same at 49%. Thus, this anti-Cap antigen-capture ELISA is able to be used for the rapid identification of BFDV-infected birds in a non-invasive manner.