Goats are highly susceptible to Mycobacterium tuberculosis complex (MTBC) infection and can play an important role in the epidemiology of animal tuberculosis (TB) in certain epidemiological scenarios. Historically, culture has been considered the only gold standard technique for post-mortem confirmation of MTBC infection. However, it is constrained by its low sensitivity, the slow growth of MTBC, and stringent biosecurity requirements. Thus, alternative post-mortem techniques are essential for effective TB control and eradication. This study aimed to compare the use of different diagnosis techniques for post-mortem confirmation of MTBC infection in goats positive for official tuberculin skin tests (TST). The techniques evaluated were direct tissue real-time polymerase chain reaction (RT-PCR), culture, observation of gross and histopathological tuberculosis-like lesions (TBL), and Ziehl-Neelsen staining. Lung and retropharyngeal and mediastinal lymph node (LN) samples were taken from 205 TST-positive goats. Direct tissue RT-PCR showed the highest rate of positive animals for post-mortem confirmation of TB infection (86.3 %) after the official in vivo diagnostic test, followed by histopathological (49.3 %), and gross (47.8 %) observation of TBL, MTBC culture (42.4 %) and ZN staining (8.5 %). Spoligotyping was obtained for 86 of the mycobacteria cultures, revealing SB0157 in 86.0 % (74/86) and SB1081 in 15.1 % (13/86) of them, both belonging to Mycobacterium caprae. Histopathological study showed a predominance of necrotic TBL in 85.2 % (52/61) and 83.5 % (66/79) of the granulomas observed in lung and LN samples, respectively. Our results indicate that direct RT-PCR on tissue is a sensitive and reliable technique for post-mortem confirmation of MTBC infection in the caprine TB control and eradication programs, even in animals without TBL.

The Iberian lynx population has been increasing in recent years thanks to the collaboration of several associations within the framework of the Life Lynxconnect project, which promotes captive breeding for the subsequent release of specimens into the environment. It is therefore important to know their population status, the diseases to which these animals are exposed and how they affect their repopulation. In this sense, this study aims to study how the presence of mycobacteria affects the lynx population in Extremadura (southwest of Spain). Up to date, our findings show the absence of tuberculosis (TB) in all lynxes tested, while they seem to be reservoirs of non-tuberculous mycobacteria (NTM), mainly M. lentiflavum, the most isolated species.

The Iberian lynx (Lynx pardinus) population has been increasing in recent years thanks to the collaboration of several associations within the framework of the Life Lynxconnect project, which promotes captive breeding for the subsequent release of specimens into the environment. It is therefore important to know their population status, the diseases to which these animals are exposed, and how they affect their repopulation. In this sense, this study aims to study how the presence of mycobacteria affects the lynx population in Extremadura (southwest of Spain). To this end, blood samples, tracheal swabs, and tracheobronchial washings from live-captured lynxes, as well as mediastinal and mesenteric lymph nodes from roadkill animals, were collected. The association between the presence of mycobacteria and various factors—including body condition, age, sex, and blood parameters—was subsequently evaluated. Up to date, our findings show the absence of tuberculosis (TB) in all lynxes tested, while they seem to be reservoirs of non-tuberculous mycobacteria (NTM), mainly M. lentiflavum, the most isolated species. Nonetheless, these mycobacteria appear to have no significant effect on the health condition of the animals.

The isolation of non-tuberculous mycobacteria (NTM) is common in cattle positive for tuberculosis (TB) in official diagnostic tests, whereas data on specific NTM species in Spanish cattle remain limited. This study identifies the most frequently isolated NTM species from Single Intradermal Tuberculin Test (SITT)-positive cattle in Extremadura, western Spain. Among 1669 Mycobacterium Growth Indicator Tube (MGIT) positive cultures collected in 2018, 493 (29.54 %) were identified as NTM, and 194 were randomly selected for further analysis. Polymerase Chain Reaction (PCR)-restriction analysis of the hsp65 gene and partial sequencing of 16S ribosomal DNA (rDNA) confirmed a diverse range of species. The most prevalent complex was Mycobacterium avium (40.12 %), including M. senriense, M. intracellulare, and M. avium subsp. paratuberculosis. Other notable NTM species (23.35 %) included M. bourgelatii, M. kansasii, M. gordonae, and M. shinjukuense. Less frequent complexes included M. simiae (11.38 %), M. ulcerans (3.59 %), M. parafortuitum (2.99 %), and M. terrae (1.20 %), along with M. holsaticum (1.20 %), a species related to the M. tuberculosis complex. Phylogenetic analysis and geographic mapping revealed weak correlation between genetic and geographic distances (Mantel test: R_xy = 0.015, P = 0.253), suggesting limited spatial structuration of genetic diversity. Alpha diversity metrics indicated moderate diversity (Shannon's H = 2.641, Simpson's D = 0.106), with some zones exhibiting greater species evenness. Diversity analyses showed moderate dissimilarity among clusters. These findings enhance understanding of Mycobacterium diversity and distribution while emphasizing the diagnostic challenges posed by NTM in TB detection and the importance of molecular tools in species identification and epidemiological surveillance.