Pulmonary nocardiosis in an orangutan.

Pulmonary nocardiosis was diagnosed in an adult male orangutan (Pongo pygmaeus) being maintained in an outdoor facility. Periodically, the orangutan had had clinical signs of an upper respiratory tract infection, as evidenced by slight nasal discharge and cough. At the terminal stage, the orangutan had acute respiratory embarrassment, with epistaxis, and died before diagnosis could be made and treatment initiated. Gross necropsy findings included fibrosis of the pulmonary parenchyma as well as evidence of air sac infection, extensive pneumonia, and extensive chronic pleuritis. Microscopically, some of the lung sections had alveoli filled with polymorphonuclear cells, with other sections being diffusely fibrotic; the areas of fibrosis contained interspersed foci of polymorphonuclear cell infiltration. Many of the latter areas contained organism colonized in the form of granules that resembled those seen in actinomycosis. These organisms were gram-positive and branched, and measured close to 1 mum in diameter. Nocardia asteroides was isolated from the pulmonary tissue.