The salient finding from this study is the decreasing trend in prevalence of PTB in Saharia tribal community of central Indian state of Madhya Pradesh. Analysis of data on burden of disease caused by TB and the effectiveness of programmatic efforts to reduce this burden are crucial for public health action [11]. Further, this analysis is essential for programme evaluation which helps guide decisions about TB control management activities and policy. It supports TB control programme managers to monitor trends in the number and distribution of TB cases across the region. This enables TB control activities to report on the country’s TB epidemic and progress in reaching TB control goals and objectives. It also helps TB control programme managers to develop targeted national strategies and budget plans.
The current finding from community based prevalence survey highlight alarmingly high TB disease burden among Saharia tribe as compared to the national average and different population groups within the country [5]. This finding corroborate with the global evidences of high burden of TB among indigenous population [12]. The incidence of TB among indigenous peoples in Latin America was 1000/100000 and it was around 20 times higher than the incidence in the general population [13]. Among Yanomami people found the incidence of TB to be 2133/100000, or 37 times higher than in the surrounding non-indigenous population [14]. Indigenous people living in Cotopaxi Province in Ecuador’s highlands had TB prevalence rates reaching 6700/100000 [15].
It is encouraging that the repeat survey showed reduction in TB prevalence suggesting that efforts to improve TB control through active case finding was one of the important contributory factor in reducing the prevalence. The study from south India reported substantial reduction in TB prevalence in 5 years with DOTS implementation along with active case finding in the population [16, 17]. The tribal population in India also has access to free DOTS under RNTCP. This could be a plausible factor behind decreasing trend of TB among this vulnerable population. The analysis of national surveys conducted during 1990–2012 in Asia show 50% decrease in TB disease within a period of 10 years with some countries showing even greater decline with the available intervention techniques and methods [18].
However, the reduction among elderly population is less as compared to other age group particularly culture positive TB. It has been reported that smear positive TB is less in elderly and there are more chances for adverse drug reactions, default or death of newly diagnosed TB cases in this age group [19, 20]. Policy makers, in consultation with all the stakeholders, should consider developing specific intervention strategies for TB management in this population group. At the same time, the studies are also required to understand the effect of such interventions on the possible concentration of cases in this group. Given that TB prevalence was high among the elderly, there is a need to step up efforts to manage this vulnerable population.
The current study finding of reduction in TB prevalence occurred in a very short period, whereas the findings from four countries (Cambodia, China, the Philippines and Republic of Korea) demonstrated that approximately 50% reductions in TB prevalence can be achieved within 10 years [21,22,23]. Our findings could be understood in different programmatic context. India’s RNTCP’s DOTS strategy covered the entire country in 2006 and considering the high burden of TB among tribal population and structural barrier for diagnosis and treatment of TB in tribal areas, a tribal action plan was developed and implemented in parallel under RNTCP since 2005. Under the tribal action plan, strengthening and expansion of additional health facilities and involvement of community health workers was ensured. In addition, among Saharia population in Shivpuri district, IEC campaigns and door-to-door active TB case detection survey were implemented. The reduction in TB burden among this population could be due to the cumulative effect of all these interventions.
The study population is economically poor, socially marginalized, living far away from the main locality. There are numerous challenges that this population face in accessing healthcare facility which includes poverty, shortages of healthcare workers, non-availability of medicines, higher transportation cost, work absenteeism, lack of awareness on health facility and availability of treatment. Under the RNTCP Tribal Plan, additional decentralization of diagnosis and treatment services and special incentives to the health workers for tribal areas are provided [24]. The programme performance in the area has shown gradual improvement since implementation of RNTCP with an increase in the case detection rate from 121% in 2005 to 159% in 2017 and in the cure rate from 67% in 2005 to 83% in 2017 [25, 26]. Way back in 1989, Styblo had also highlighted the challenge before the policy makers that a significant cure rate among smear positive pulmonary TB cases is pre-requisite to achieve overall improvement in TB burden in developing countries [23]. It is important to have regular and effective monitoring in place in order to understand the effects of the intervention strategies – the improvements or otherwise in disease trend. The surveys carried out at regular intervals may also help in understanding the trend.
Limitations of the study
The information on socioeconomic change in the community was not available and so its possible impact could not be assessed. Moreover, this evidence is generated from the Saharia tribe where HIV infection and MDR-TB are not highly prevalent [8, 27]. Our conclusion therefore, cannot be generalized to all areas, especially to those with a high prevalence of HIV infection or MDR-TB and non-tribes.