First Report of Mycobacterium bovis and Nocardia spp. Co-Infection in a Roan Antelope.

Nocardia spp. and Mycobacterium spp. are known etiological agents of granulomatous pulmonary infections in humans and animals; however, co-infections involving these pathogens have not previously been reported in veterinary medicine. This paper describes the first documented case of co-infection with Mycobacterium bovis and Nocardia spp. in a captive roan antelope (Hippotragus equinus). The animal was a 9-year-old female roan antelope from a safari park in northern Italy that died suddenly with a one-month history of weight loss. Post-mortem examination revealed severe, diffuse, chronic granulomatous pneumonia associated with fibrino-granulomatous pleuritis and granulomatous pericarditis. Histologically, multifocal to coalescing necrotizing granulomas were observed, with intralesional acid-fast bacteria. Microbiological culture and biomolecular analyses allowed the identification of M. bovis and Nocardia spp. in lung tissue samples. The Nocardia genome sequence was 98.5% similar to N. tengchongensis, a recently discovered species. The findings emphasize the importance of comprehensive diagnostic approaches in animal granulomatous lung disease. Mixed infections in captive wildlife represent a One Health concern, as the potential for zoonotic adaptation and transmission to humans cannot be excluded. Therefore, pathogen surveillance is of particular importance within zoological collections.