Avian polyomavirus infection of a fledgling budgerigar (Melopsittacus undulatus) and differential diagnoses of viral inclusions in psittacine birds - case report and mini-review = Aviäre Polyomavirusinfektion bei einem jungen Wellensittich (Melopsittacus undulatus) und Differenzialdiagnostik viraler Einschlusskörperchen in Psittaciden - Fallbericht und Mini- Review

A two-week-old budgerigar (Melopsittacus undulatus) of an outdoor aviary diedsuddenly and was submitted for determination the cause of illness and death.Macroscopically, the sparsely feathered animal was in a poor body condition.Histopathological examination revealed in various mesenchymal and epithelialtissues, numerous up to 15 amp;#956;m in diameter large intranuclear, amphophilic tobasophilic inclusion bodies with a clearing of the centre. Additionally, a featherdysplasia and retention hyperkeratosis of feather follicles was found. Ultrastructurally,viral particles of approximately 35 nm in diameter were detected in thefeather follicle epithelium. A PCR for Avian Polyomavirus on fresh skin sampleswas negative whereas on formalin-fixed kidney samples with a high amount ofviral inclusion bodies yielded a positive result. In addition, viral inclusion bodydiseases, like Avian Poxvirus, Psittacine Beak and Feather disease virus, AvianAdenovirus, Psittacine Herpesvirus and papillomavirus of psittacines are summarizedand compared in the present article