Prevalence of Bovine Tuberculosis in Slaughtered Cattle in Sicily, Southern Italy

Simple Summary Mycobacterium bovisis a Gram-positive, acid-fast bacterium responsible for disease in cattle and in several other domestic and wild animal species, also representing a prominent cause of morbidity and mortality in humans. In Italy, the incidence of bovine tuberculosis (bTB) in cattle has been progressively reduced throughout the years; however, the disease still remains widespread in Southern Italy, with the highest prevalence rates recorded in Sicily. Specific eradication programs have been established, with herd testing and post-mortem inspection at the slaughterhouse used as diagnostic procedures to obtain epidemiological data on bTB prevalence. The concomitant use of these procedures is essential in epidemiological surveillance programs, and although data on disease prevalence at herd level are systematically collected and used for epidemiological surveillance in Sicily, data from post-mortem inspection are scant. Therefore, the current survey aimed to investigate the prevalence of bTB in cattle in Sicily during two different three-year periods, using data from meat inspections and histopathological methods. Results obtained show that even though bTB occurrence in cattle was well reduced over the years, the disease still remains widespread in this region, posing severe implications for public health and a prominent economic impact on the livestock industry. Post-mortem inspection in slaughterhouses plays a key role in the epidemiological surveillance of infectious diseases, including bTB. This study assessed the prevalence of bTB in cattle in Sicily during two different three-year periods (2010-2012; 2017-2019), using data from meat inspections and histopathological methods. Out of 100,196 cattle, 5221 (5.21%) were diagnosed with tuberculous lesions. Higher prevalence of bTB was recorded during the triennium 2010-2012 (6.74%;n= 3692) compared to the triennium 2017-2019 (3.36%;n= 1529), with a decreasing trend in annual occurrence throughout the study period and a heterogenous proportion of infected cattle among the Sicilian provinces (p< 0.01). Lower rates of infection were recorded in animals aged 84 months (p< 0.0001). Pearson's chi square analysis revealed a higher localization of lesions in the thoracic cavity (p< 0.0001). Gathered findings show that even though bTB occurrence in cattle was greatly reduced over the years, the disease still remains widespread in Sicily, also posing severe implications for public health.