Psittacine beak and feather disease syndrome in a cockatoo.

Psittacine beak and feather disease syndrome was diagnosed in an adult sulfur-crested cockatoo with a history of chronic, progressive feather loss and beak necrosis. A definitive diagnosis was made on the basis of clinical signs and the observation of intracytoplasmic and intranuclear inclusions in involved feather follicular epithelium. Psittacine beak and feather disease syndrome develops in a variety of psittacine species and usually has a progressive and irreversible clinical course. Symmetric feather loss with replacement by severely dystrophic plumage is the salient clinical finding. Beak elongation and breakage also may be found. Treatment of diseased birds remains palliative and consists of a controlled environment, balanced nutrition, antibiotics, and autogenous vaccines. Avian practitioners should include psittacine beak and feather disease syndrome as a potential cause for pathologic feather loss in caged birds.