Tuberculosis situation among tribal population of Car Nicobar Island, India, 15 years after intensive tuberculosis control project and implementation of a national tuberculosis programme
M.V. Murhekar, C. Kolapan, P.G. Gopi, A.K. Chakraborty, & S.C. Sehgal
To assess the tuberculosis (TB) situation in the tribal community of Car Nicobar 15 years after the national TB programme was implemented in this area after an intensive phase of TB control in 1986.
The entire population of Car Nicobar Island was enumerated through a house-to-house survey. Children aged ≤14 years were tuberculin tested and read for reaction sizes. Individuals aged ≥15 years were asked about the presence of chest symptoms (cough, chest pain, and unexplained fever for two weeks or longer and haemoptysis), and sputum samples were collected from patients with chest symptoms. Sputum samples were examined for presence of acid-fast bacilli.
Among the 4543 children enumerated, 4351 (95.8%) were tuberculin tested and read. Of the 981 children without bacille Calmette–Guérin scars, 161 (16.4%) were infected with TB. A total of 77 cases who were smear-positive for TB were detected from among 10 570 people aged ≥15 years; the observed smear-positive case prevalence was 728.5 per 100 000. The standardized prevalence of TB infection, annual risk of TB infection, and prevalence of cases smear-positive for TB were 17.0%, 2.5%, and 735.3 per 100 000, respectively.
The prevalence of TB infection and smear-positive cases of TB increased significantly between 1986 and 2002. Such escalation took place despite the implementation of the national TB programme on this island, which was preceded by a set of special anti-TB measures that resulted in sputum conversion in a substantially large proportion of the smear-positive cases prevalent in the community. The most likely reason for the increase seems to be the absence of a district TB programme with enough efficiency to sustain the gains made from the one-time initial phase of special anti-TB measures. High risk of transmission of TB infection currently observed on this island calls for a drastic and sustained improvement in TB control measures.