Tuberculosis (TB) in animals is a re-emerging disease with a wide range of hosts that causes large economic losses in livestock. Goats are particularly susceptible to TB and, in endemic areas, vaccination may be a valuable measure to control the disease. The main aim of this study was to evaluate the efficacy of parenteral vaccination of goats with a heat-inactivated Mycobacterium bovis (HIMB) vaccine, and compare it to M. bovis Bacille Calmette–Guérin (BCG) vaccine. Twenty-four goat kids were divided in 3 groups as following: HIMB vaccinated group (n = 8), BCG vaccinated group (n = 8) and unvaccinated group (n = 8). Afterwards, goats were experimentally challenged with Mycobacterium caprae by the endobronchial route. Antigen specific interferon-γ release assays and serology were performed after vaccination and challenge. Pathological and bacteriological parameters were evaluated after necropsy at 9 weeks post-challenge (p.c.). HIMB vaccine showed similar levels of protection to BCG in terms of volume reduction of thoracic TB lesions, presence of extra-pulmonary lesions, as well as a slight reduction of bacterial load in pulmonary lymph nodes. Moreover, HIMB vaccine did not induce interferences on the interferon-γ release assay based on reagents previously developed to differentiate infected from BCG vaccinated individuals. The results indicate that HIMB is a suitable vaccine candidate for further larger-scale trials under field conditions in goats.

Increasing number of caprine tuberculosis (TB) reports grant the consideration of this zoonosis as an emerging disease that can play a role in the epidemiology of bovine TB in endemic areas. An outbreak of TB was detected in a caprine/ovine dairy mixed herd. Tuberculin skin test positive goats and ewes were euthanized and subsequent postmortem investigations were performed. Mycobacterium caprae (spoligotype profile SB0157) was isolated from tuberculous lesions detected in both sheep and goats. Our findings evidenced the direct transmission of the infection between both species elucidating that not only goats but also sheep may act as domestic reservoirs of TB compromising the eradication of TB in cattle. The results have implications for animal TB epidemiology and public health risk management.