Human Mycobacterium bovis infection in Castile and León (Spain), 2006-2015.

INTRODUCTION: The annual incidence of tuberculosis (TB) from Mycobacterium bovis in humans has considerably declined in industrialised countries since the early twentieth century. The objective of this study was to determine the epidemiological, clinical and microbiological characteristics of patients with this illness in Castile and León (CyL).

METHODS: Retrospective study of all M. bovis TB cases in CyL over a 10-year period, comparing the risk factors, the epidemiology and the clinical course between pulmonary (PTB) and extrapulmonary TB (EPTB).

RESULTS: 75 cases of TB were due to M. bovis: 45 PTB and 31 EPTB. The annual incidence of TB due to M. bovis was 0.3 cases per 100,000. It remained stable between the first and second five-year period (0.27 vs. 0.33, p=0.656). However, the overall incidence of TB fell in both five-year periods (13.58 vs. 10.71, p<0.0001). The mean age was 66.2+21.3 years, mainly men (63%) and Spanish patients (92%). PTB was significantly more frequent in men, aged over 66 years, with immunosuppressive conditions or who were smokers. Mortality was 9%, associated with higher age, immunosuppression or treatment different from that recommended by the WHO.

CONCLUSIONS: The incidence of M. bovis TB in CyL was higher than that for Spain and for other European countries, and remained stable despite the decreased the TB due to MTC. It affected mostly Spanish-born patients who lived in rural areas and with a high mean age.