Avian tuberculosis in a free-living Eurasian griffon vulture

Abstract

Although Mycobacterium spp. often cause disease in domestic birds (chickens and companion birds), there are few data on avian tuberculosis in wild populations, especially in birds of prey. We describe here a case of a young adult female, free-living Eurasian griffon vulture (Gyps fulvus) that was found dead. Granulomas were grossly evident in the lungs at autopsy, and tuberculosis was suspected. Ziehl-Neelsen staining revealed large numbers of intracellular acid-fast-positive bacteria within granulomas. Examination on Löwenstein-Jensen medium was negative, but mycobacteria growth indicator tube medium results were positive. For the molecular detection of Mycobacterium spp., the primer set IS901F and IS901R was used. Positive results were observed on gel electrophoresis, indicating the presence of Mycobacterium avium subsp. avium DNA. Although tuberculosis is not considered to be a common cause of death in wild birds, it undoubtedly deserves special attention because vultures are generally considered to be a species resistant to a large number of pathogens. Determination of the cause of death of griffon vultures is important for future conservation measures for this sensitive wild species.

Keywords: Gyps fulvus; Mycobacterium avium; PCR; bacteriology; histopathology.

Figure 1.

Avian tuberculosis in a Eurasian griffon vulture. A. Pulmonary granulomas, with caseous, necrotic centers. B. Granulomas with a centrally located necrotic mass, in the spleen. C. A pulmonary granuloma surrounded by multinucleate giant cells and epithelioid cells. H&E. Bar = 200 μm. D. Acid-fast mycobacteria in a section of air sac. Ziehl–Neelsen stain. Bar = 50 μm.