Psittacine beak and feather disease infected cells show a pattern of apoptosis in psittacine skin.

Skin biopsies from 23 birds with psittacine beak and feather disease (PBFD) were examined by light and electron microscopy. Affected cells, preferentially found in the cell layers of the feather follicles, could be clearly identified by the presence of intracytoplasmic virus inclusion bodies. Ultrastructurally, the degenerative process in these cells was morphologically suggestive of apoptosis.