Mycobacterium bovis induced human tuberculosis in India: Current status, challenges & opportunities

Tuberculosis (TB) caused by Mycobacterium tuberculosis is a leading cause of human deaths due to any infectious disease worldwide. However, infection of Mycobacterium bovis, primarily an animal pathogen, also leads to the development of ‘human tuberculosis’. Infected animals have been considered the major source of M. bovis infection and humans get exposed to M. bovis through close contact with infected animals or consumption of contaminated milk, unpasteurized dairy products and improperly cooked contaminated meat. The information on the global distribution of bovine TB (bTB) is limited, but the disease has been reported from all the livestock-producing middle- and low-income countries of the world. In recent years, there is a renewed interest for the control of bTB to minimize human infection worldwide. In India, while the sporadic presence of M. bovis has been reported in domestic animals, animal-derived food products and human beings from different geographical regions of the country, the information on the national prevalence of bTB and transmission dynamics of zoonotic TB is, however, not available. The present article reviewed published information on the status of M. bovis-induced zoonotic TB to highlight the key challenges and opportunities for intervention to minimize the risk of M. bovis infection in humans and secure optimum animal productivity in India.

Tuberculosis patients co-infected with Mycobacterium bovis and Mycobacterium tuberculosis in an urban area of Brazil

In this cross-sectional study, mycobacteria specimens from 189 tuberculosis (TB) patients living in an urban area in Brazil were characterised from 2008-2010 using phenotypic and molecular speciation methods (pncA gene and oxyR pseudogene analysis). Of these samples, 174 isolates simultaneously grew on Löwenstein-Jensen (LJ) and Stonebrink (SB)-containing media and presented phenotypic and molecular profiles of Mycobacterium tuberculosis, whereas 12 had molecular profiles of M. tuberculosis based on the DNA analysis of formalin-fixed paraffin wax-embedded tissue samples (paraffin blocks). One patient produced two sputum isolates, the first of which simultaneously grew on LJ and SB media and presented phenotypic and molecular profiles of M. tuberculosis, and the second of which only grew on SB media and presented phenotypic profiles of Mycobacterium bovis. One patient provided a bronchial lavage isolate, which simultaneously grew on LJ and SB media and presented phenotypic and molecular profiles of M. tuberculosis, but had molecular profiles of M. bovis from paraffin block DNA analysis, and one sample had molecular profiles of M. tuberculosis and M. bovis identified from two distinct paraffin blocks. Moreover, we found a low prevalence (1.6%) of M. bovis among these isolates, which suggests that local health service procedures likely underestimate its real frequency and that it deserves more attention from public health officials.

La tuberculosis zoonótica en la Argentina / Zoonotic tuberculosis in Argentina

Existen importantes logros en el control de la tuberculosis (TB) animal en la Argentina. Los porcentajes de bovinos con lesiones TB halladas en mataderos disminuyeron de 6.7% a 0.7% entre 1969 y 2011. En salud pública, el porcentaje promedio de TB por M. bovis sobre el total de los casos confirmados bacteriológicamente, fue en Santa Fe -provincia agro industrial- 2.3% en el período 1977-2001 y 1.6% entre 2002 y 2011. En Buenos Aires, en el Hospital Cetrángolo, ese porcentaje fue 0.34% (2001-2005) y 0.36% (2006-2011). En el Hospital Muñiz disminuyó de 1.75% en 1971 a 0.22% en 2006. La frecuencia de HIV entre los casos de M. bovis varió de 5.9% en Santa Fe a 11.1% y 20.5% respectivamente en los Hospitales Cetrángolo y Muñiz de Buenos Aires. En conjunto, la infección por M. bovis es más importante en las zonas rurales/ agro industriales, con un lento descenso, también observado en Buenos Aires. La coinfección por HIV es más frecuente en pacientes con M. bovis que en el conjunto de los casos de TB. Comparando la situación de la Argentina con la de EE.UU. y países de Europa y América Latina, se observa que las tendencias de la TB en el ganado, en humanos y la frecuencia relativa del M. bovis en salud pública, no siempre siguen una relación estrecha. Para avanzar hacia la meta común de erradicación de la TB, el empleo de estrategias adecuadas y el fortalecimiento de las medidas de control son fundamentales para ambos programas.

There are significant achievements in the control of animal tuberculosis (TB) in Argentina. The percentage of bovines with apparent TB lesions at the slaughterhouse inspection decreased from 6.7% to 0.6% between 1969 and 2011. On the other hand, the mean percentage of human TB cases due to M. bovis among all those bacteriologically confirmed, was in Santa Fe, an agro-industrial province, 2.3% in the period 1977-2001. It fell to 1.6% by 2011. In the Cetrángolo Hospital (Buenos Aires), it was 0.34% in the period 2001-2005, and 0.36% in 2006-2011. At the Muñiz Hospital, these percentages decreased from 1.75% in 1971 to 0.22% in 2006. Frequency of HIV infection among M. bovis cases varied from 5.9% in Santa Fe to 11.1% and 20.5% respectively, in Cetrángolo and Muñiz Hospitals (a reference institution for aids) in Buenos Aires. According to these data M. bovis infection predominates in agro- industrial/ rural areas, showing a slow decrease there as well as in Buenos Aires. Co-infection with HIV is more frequent among patients with M. bovis that in all cases of TB. The situation of M. bovis in Argentina is here compared with that in USA and in several European and Latin American countries. Trends followed by TB in cattle, in humans, and the percentages of M. bovis among them, are not always closely related. To move towards the common goal of eradicating TB, the employment of appropriate strategies and the strengthening of control measures are critical in both programs.