Relatedness between host species and genotype of beak and feather disease virus suggesting possible interspecies cross infection during bird trade.

Beak and feather disease virus (BFDV) is a causative agent of psittacine beak and feather disease (PBFD), which shows a characteristic feather disorder in psittacine birds. In the present study, the subclinical infection rate of PBFD in imported and domestically bred psittacine birds was investigated by polymerase chain reaction. As a result, 126 of 402 birds (31.3%) were found to be BFDV positive. The DNA sequences of the part of open reading frame (ORF) C1 were determined for 16 BFDV-positive randomly selected samples. One of 16 samples was found to have a mixed infection, and 5 different BFDV sequences were obtained from a single African grey parrot. In phylogenic analysis, almost BFDV sequences included in each genetic cluster of phylogenic tree belonged to the same psittacine subfamily. BFDV derived from African grey parrot was closely related to the BFDV derived from cockatoos by way of exception. The natural habitat of the African grey parrot and cockatoos is different, and therefore, the possibility of interspecies cross infection through the bird trade is suggested from the exceptional BFDV sequences.