Fig. 5.

IHC staining directed against avian Bornavirus nucleoprotein in the cerebrum of an African gray parrot (P erithacus) with PDD. The nuclei and cytoplasm of numerous neurons have stained positively (red-brown color), as has the dendritic tree of a large neuron (solid arrows). Viral antigen is widely distributed and can be seen within perivascular cuffs (open arrows) but also in areas without microscopic lesions (original magnification ×400).