Recently, Avian bornavirus (ABV) was detected in proventricular dilatation disease (PDD) affected-birds and feather picking diseases affected-birds. However, the pathogenicity of ABV has not been thoroughly investigated. In this study, we surveyed ABV in pet birds in Japan. We found four ABV-infected birds among 93 pet birds using RT-PCR, and genotypes of the ABV were determined as ABV-2 and -4. Two of the birds positive for ABV-4 showed proventricular dilatation typically found in PDD, and chronic stomach disturbance, whereas two of the birds positive for ABV-2 showed unexplained behavioral problems that are tapping, autophagia, and cloaca prolapse.

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ABSTRACT. Avian bornaviruses (ABVs) were recently discovered as the causative agents of proventricular dilatation disease (PDD). Although molecular epidemiological studies revealed that ABVs exist in Japan, no Japanese isolate has been reported thus far. In this study, we isolated four strains of Psittaciform 1 bornavirus from psittacine birds affected by PDD using QT6 quail cells. To our knowledge, this is the first report to isolate ABVs in Japan and to show that QT6 cells are available for ABV isolation. These isolates and QT6 cells would be powerful tools for elucidating the fundamental biology and pathogenicity of ABVs.

Chlamydia -related bacteria of the Chlamydiales order have recently been described as emerging pathogens that cause pneumonia and abortion in animals and humans. We investigated the presence of Chlamydiales using real-time polymerase chain reaction (PCR) by targeting the 16S rRNA gene of a broad range of Chlamydiales in 827 fecal samples from pet birds kept in individual homes in Japan. Of the 827 samples, 493 (59.6%) tested positive for the Chlamydiales 16S rRNA gene in the real-time PCR assay. We determined the nucleic acid sequences of PCR products from 17 Chlamydiales strains. A homology search and phylogenetic analysis using these sequences confirmed that the detected Chlamydiales included C. pecorum and a broad range of Chlamydia -related bacteria. To the best of our knowledge, this is the first study to detect a wide range of Chlamydia -related bacteria in birds.