Natural nocardial infection has been reported in many different species including mammals and fish.5,7 Reports in birds remain uncommon.1-6
From September 1996 to February 1997 eight juvenile black crakes (Limnocorax flavirostra) from a group of 12 died unexpectedly at the Basel Zoo. The birds had been housed in an aviary together with a pair of red-billed hornbills (Tokus erythrorhynchus). The exhibit consisted of an outdoor cage with a natural sand ground, and an indoor part with a substrate of chopped bark. The volume of the aviary was approximately 110 m3.
Necropsy revealed that five of the submitted crakes were in poor body condition. Disseminated white, raised, firm, well-circumscribed nodules 1–3 mm in diameter were noted throughout the lung parenchyma of all birds. Furthermore, a severe splenomegaly was observed. Histologically, the lungs had multiple, often confluent, granulomas with moderate to severe central necrosis. The necrotic center was surrounded by a margin composed of heterophils, macrophages, lymphocytes, and some multinucleated giant cells. Various numbers of delicate, gram-positive, 0.5–1.0 µm wide, branching, occasionally beaded, filamentous organisms were visible in the necrotic centers. These organisms were acid-fast if stained with Fite-Faraco, but not with the Ziehl-Neelsen acid-fast stain. No histologic lesions were seen in the other organs.
A microbiological examination was carried out in three cases and Nocardia asteroides nova was isolated from samples of the liver, spleen, kidney, and lung. A diagnosis of severe granulomatous and necrotizing nocardial pneumonia with agonal septicemia was made. This suggests an aerogenous infection.
Fecal samples were collected at necropsy and from crakes in the aviary. No parasites were detected with flotation, sedimentation, and direct mount examination.
To resolve the problem in the exhibit, the aviary was cleaned, disinfected, and the chopped bark was changed. To our knowledge, epizootic outbreaks of nocardiosis in birds are not reported in the literature. Whether nocardiosis is a truly rare disease in birds, or is simply not recognized, is unknown. In the past, nocardiosis has often been confused with Mycobacterium, Actinomyces, and Streptomyces infections in both animals and man.
1. Baumgartner R, Hoop RK, Widmer R. Atypical nocardiosis in a red-lored amazon parrot (Amazonia autumnalis autumnalis). JAVMA. 1994;8(3):125–127.
2. Bergmann A, Schüppel KF, Kronberger H. Nocardiose bei einem Türkisvogel (Cyanerpes cyaneus). Verh Ber Int Symp Erkrank Zootiere. 1977;15:293–296.
3. Ehrsam H, Hauser B. Nocardiose bei Blauflügel-Königssittichen (Alisterus amboinensis hypophonius). Schweiz Archiv Tierheilkd. 1979;121:195–200.
4. Long P, Choi G, Silberman M. Nocardiosis in two Pesquet’s parrots (Psittrichas fulgidus). Avian Dis. 1983;27(3):855–859.
5. Parnell MJ, Hubbard GB, Fletchter KC, Schmidt RE. Nocardia asteroides infection in a purple throated sunbird (Nectarinia sperata). Vet Pathol. 1983;20:497–500.
6. Sileo L, Sievert PR, Samuel MD. Causes of mortality of albatross chicks at Midway Atoll. J Wildl Dis. 1990;26(3):329–338.
7. Walton AM, Libke KG. Nocardiosis in animals. Vet Med Small Anim Clin. 1974;69(9):1105–1107.