Tissue Distribution of Parrot Bornavirus 4 (PaBV-4) in Experimentally Infected Young and Adult Cockatiels (Nymphicus hollandicus)

Parrot bornavirus (PaBV) causes proventricular dilatation disease (PDD) of birds, causing predominantly nervous and gastrointestinal symptoms. PDD is fatal disease for birds. In order to detect the relevancy between the age of the animals at the time of infection and the PDD distribution in the body, we infected PaBV-4 to adults (group 1) 11 cockatiels and 11 juveniles (group 2) cockatiels by intravenous injection. In both cohorts, adult and juvenile PaBV-4-infected cockatiels, a widespread antigen and RNA tissue distribution was present. The results indicate that the virus spreads possibly not only via nerve tissue, but potentially also via endothelial cells, fibrocytes, and smooth muscle cells. Also, the histological lesions indicate that an age-related course of infection with more severe lesions in the CNS of adults but marked inflammation in gastrointestinal tract of juveniles despite lacking clinical signs. This contributes to understand the development of various clinical or non-clinical disease patterns and the development of carrier birds when infected as juveniles.

(RN)