Background:
Tuberculosis (TB) elimination program in India relies on detecting symptomatic patients through molecular diagnosis and providing speedy treatment, leaving individuals with no classical symptoms of TB (asymptomatic) behind in the population. Considering the contribution of such asymptomatic individuals to transmission of TB, it is important to timely identify them, especially in high-endemic settings. However, no community-level study has so far been conducted to record the incidences of asymptomatic cases in India. Therefore, this study was planned to know whether Mycobacterium tuberculosis, the causal pathogen of TB is prevalent in individuals presenting no classical symptoms in a highly endemic populations belonging to Saharia tribe, a Particularly Vulnerable Tribal Group (PVTG) in India.
Methods:
We performed molecular epidemiological study in 15 villages (n= 808) of Pohri block, Shivpuri district, Madhya Pradesh, India following population-wide random sampling of both symptomatic (ns=216) and asymptomatic (na=592) individuals. Though a total of 890 subjects were involved in the study, the sputum samples for the qPCR test could be collected only from 808 subjects. Detection of M. tuberculosis in sputum samples was done using TaqMan chemistry-based qPCR assay.
Results:
Sixteen (2.7%) individuals were found to be positive of M. tuberculosis among the 592 asymptomatic cases. The prevalence of M. tuberculosis DNA positivity was comparable between symptomatic (2.3%) and asymptomatic (2.7%) individuals.
Conclusion:
The present findings, though preliminary, pending large-scale screening approaches in other high-endemic populations employing both classical and advanced diagnosis methods, are daunting. Such community-wide screening approaches should therefore be integrated in the program if TB-free India is to be achieved by the year 2025.
Immunological and Molecular Diagnosis of Mycobacterium tuberculosis Between two Environmentally Different Regions
