An epornitic of avian pox in a research aviary.
Although 10 species of passerine birds were present, clinical signs and mortality were restricted to canaries and house sparrows. PM lesions initially occurred in the upper and lower respiratory tract, with proliferative rhinitis, proliferative bronchopneumonia and proliferative airsacculitis. Diphtheritic lesions in the oesophagus were proliferative, granulomatous oesophagitis. Cutaneous lesions occurred subsequently in some birds, and a diagnosis was made by histopathology, electron microscopy, and virus isolation. The occurrence of diphtheritic lesions in pox infections of wild birds is rare, and a sparrow showed an unusual combination of both diphtheritic and acute systemic lesions not previously described.