Disseminated Mycobacteroides chelonae infection in a free-ranging jararaca (Bothrops jararaca)

Nontuberculous mycobacteria (NTM) are widely distributed in the environment and can cause infections in several animal species, including reptiles. However, reports of NTM infections in free-ranging reptiles remain scarce. This study describes the pathological and molecular findings of a disseminated Mycobacteroides chelonae infection in a free-ranging jararaca ( Bothrops jararaca ) from São Paulo, Brazil. An adult female snake found dead in the wild was submitted for post-mortem examination. Necropsy revealed multifocal to miliary yellowish granulomas in the liver and multifocal pulmonary nodules, as well as traumatic lesions. The snake was also gravid, with 32 fetuses at an advanced stage of development. Histopathological examination identified multifocal granulomatous hepatitis, granulomatous pneumonia with central necrosis, and granulomatous lesions in the splenopancreas. Ziehl–Neelsen staining revealed numerous acid-fast bacilli within hepatic and pulmonary granulomas. Molecular analysis of an 86-bp fragment of the mycobacterial hsp65 gene showed 98.85% nucleotide identity with M. chelonae sequences available in GenBank. These findings are consistent with a disseminated mycobacterial infection attributed to M. chelonae . This case expands the known occurrence of NTM infections in reptiles and highlights the value of combining necropsy, histopathology, special stains, and molecular methods in the investigation of infectious diseases in wildlife. Further studies involving additional cases and more extensive molecular characterization may help clarify the occurrence and pathological features of NTM infections in free-ranging reptiles.