Risk factors for human Mycobacterium bovis infections in an urban area of Brazil

Abstract

BACKGROUNDThe World Health Organization (WHO) has classified human zoonotic tuberculosis (TB) due to Mycobacterium bovis as a neglected issue in the developing world. In a recent cross-sectional study in Brazil, three of 189 TB patients presented with a coinfection of M. bovis and M. tuberculosis and were selected as cases for this study.OBJECTIVEThe aim was to evaluate risk factors (RF) for zoonotic TB in an urban area of Brazil in order to guide preventive programmes.METHODSA matched case-control study was carried out nested within a cross-sectional study. For each of the three cases, 14 age- and sex-matched controls (TB due to M. tuberculosis) were selected.FINDINGSZoonotic potential exposures (ZE) and extrapulmonary TB (EPTB) were independently associated with zoonotic TB in multivariate analyses.CONCLUSIONSZE by occupation and consumption of raw milk and derivative products that place individuals in direct and indirect contact with animals and their excretions/secretions increase the risk for zoonotic TB in Brazil, especially among those with EPTB. Therefore, measures such as efficient control of bovine TB, distribution of pasteurised milk and its derivative products, and the diagnosis and monitoring of zoonotic TB in humans are essential steps, especially in developing countries where bovine TB is enzootic, and further studies are necessary.

Identification of Mycobacterium bovis in patients diagnosed with pulmonary and extrapulmonary tuberculosis

“…9,10 Unlike the results of other investigations, we did not record frequency differences with regard to patient gender. 17 In emerging countries, 10 to 20 % of cases of tuberculosis are caused by Mycobacterium bovis; however, this percentage might be underestimated because most laboratories do not routinely perform mycobacterial cultures, and only few have systems to identify Mycobacterium bovis. There are few studies investigating genotypic diversity and drug resistance in Mycobacterium bovis from infections in animals or humans.…”

Bayesian Assessment of the Accuracy of a PCR-Based Rapid Diagnostic Test for Bovine Tuberculosis in Swine

“…Although significant improvements have been made in the last 20 years, control and eradication of bTB continues to be a major challenge for Latin American countries (36, 37). Furthermore, the disease has re-emerged in humans in the region, reinforcing the need to understand the role of domestic and wild animals on the disease epidemiology, and, most importantly, the need for developing new strategies to effectively and efficiently prevent and control disease spread (37–40). Some of the challenges associated with bTB diagnosis in swine include presence of fewer bacilli in bTB lesions compared to other species (41, 42), relatively high susceptibility to avian TB infection, being those lesions undistinguishable from those produced by M. bovis (20, 32), and the lack, despite some promising advances (43), of simple, affordable, and sensitive diagnostic tools to identify infected animals at the farm level, like the PPD test use routinely in cattle (43–45).…”

Identificación de Mycobacterium bovis en pacientes con diagnóstico de tuberculosis pulmonar y extrapulmonar

“…9,10 A diferencia de los resultados de otras investigaciones, no registramos diferencias en la frecuencia respecto al sexo de los pacientes. 17 En los países emergentes, 10 a 20 % de los casos de tuberculosis es causado por Mycobacterium bovis, sin embargo, este porcentaje puede ser subestimado porque la mayoría de los laboratorios no realizan rutinariamente cultivos de micobacterias y pocos cuentan con los sistemas para identificar Mycobacterium bovis. Existen pocos estudios que investiguen la diversidad genotípica y la resistencia a fármacos en Mycobacterium bovis a partir de infecciones en animales o humanos.…”