Granulomatous pneumonia due to pythiosis in captive South American coatis (Nasua nasua)

Pythiosis is an emerging infectious disease affecting captive and free-ranging wild animals. We report granulomatous pneumonia due to Pythium insidiosum in two South American coatis (Nasua nasua), who were found dead without any clinical records. Severe granulomatous pneumonia associated with pleural effusion was revealed in the necropsy. Microscopically, variably sized granulomas and pyogranulomas presented negative hyphae profiles at the periphery of their necrotic cores. Grocott methenamine silver stain highlighted these structures, and immunostain (anti- P. insidiosum) was strongly positive. Molecular analysis by polymerase chain reaction amplified P insidiosum specific DNA. These findings characterized P insidiosum as a cause of granulomatous pneumonia in coatis and proved that pythiosis needs to be considered in the differential diagnosis of respiratory diseases affecting this species in endemic areas.