Trends in the annual risk of tuberculous infection in India.

SETTING: Twenty-four districts in India. OBJECTIVES: To evaluate trends in annual risk of tuberculous infection (ARTI) in each of four geographically defined zones in the country. STUDY DESIGN: Two rounds of house-based tuberculin surveys were conducted 8-9 years apart among children aged 1-9 years in statistically selected clusters during 2000-2003 and 2009-2010 (Surveys I and II). Altogether, 184,992 children were tested with 1 tuberculin unit (TU) of purified protein derivative (PPD) RT23 with Tween 80 in Survey I and 69,496 children with 2TU dose of PPD in Survey II. The maximum transverse diameter of induration was measured about 72 h after test administration. ARTI was computed from the prevalence of infection estimated using the mirror-image method. RESULTS: Estimated ARTI rates in different zones varied between 1.1% and 1.9% in Survey I and 0.6% and 1.2% in Survey II. The ARTI declined by respectively 6.1% and 11.7% per year in the north and west zones; no decline was observed in the south and east zones. National level estimates were respectively 1.5% and 1.0%, with a decline of 4.5% per year in the intervening period. CONCLUSION: Although a decline in ARTI was observed in two of the four zones and at national level, the current ARTI of about 1% in three zones suggests that further intensification of TB control activities is required.

Selected risk factors associated with pulmonary tuberculosis among Saharia tribe of Madhya Pradesh, central India.

Tuberculosis (TB) is a major public health problem among the Saharia, a marginalized tribal group in Madhya Pradesh state, central India. However, there is no information on the risk factors associated with the development of TB disease in this community. A cross-sectional TB prevalence survey was conducted among the Saharia residing in Sheopur district of Madhya Pradesh. Information on tobacco smoking and alcohol consumption was collected from all the individuals. Persons aged ≥45 years, males, smokers and alcohol consumers had higher risks of developing TB disease. There is an urgent need to develop and implement culturally appropriate awareness raising activities to target smoking and alcohol consumption to support the efforts to control TB in this community.

Yield of culture of Mycobacterium tuberculosis complex in sputum samples transported from tribal areas.

BACKGROUND: There is little information on the recovery of Mycobacterium tuberculosis complex from sputum samples collected in the field for bacteriological examination. SETTING: Tribal areas in the State of Madhya Pradesh, in central India. METHODS: Sputum specimens collected from subjects with chest symptoms in a disease prevalence survey were refrigerated until transportation to the laboratory. The specimens were processed for microscopy and culture. The samples were grouped based on the delay in processing for culture from the day of collection into three groups: 0-3, 4-7 and ≥8 days, and the recovery of M. tuberculosis complex in these groups was analysed. The statistical analysis was performed using χ(2) test. RESULTS: Of the 3651 processed specimens, 114 were positive for M. tuberculosis complex by culture and 96 by smear microscopy. The differences in the proportion of 'smear-positive, culture-positive', 'smear-positive, culture-negative' and 'smear-negative, culture-positive' samples between the three groups were not significant. CONCLUSION: In difficult-to-reach areas with limited resources, refrigeration of sputum specimens until they are transported for processing at a reference laboratory for culture seems not to significantly affect the recovery of M. tuberculosis complex isolates.

Annual risk of tuberculosis infection among the tribal children of Jhabua, Madhya Pradesh.

A cross sectional tuberculin survey was undertaken to estimate the Annual Risk of Tuberculosis Infection (ARTI) amongst tribal children aged 1-9 years in Jhabua district, Madhya Pradesh, India. Of the 1056 test-read children, 774 (73.3%) had no BCG scar. The prevalence of infection was estimated as 6.3% (95% CI: 4.8-7.7) and ARTI as 1.2% (95% CI: 0.9-1.5). The findings suggest that the tuberculosis situation in the tribal population of Jhabua district is not that different from the situation among the non-tribal population in the country. However, there is a need to further intensify tuberculosis control measures in the area.

Prevalence of pulmonary tuberculosis amongst the Baigas--a primitive tribe of Madhya Pradesh, Central India.

BACKGROUND: A community-based cross-sectional tuberculosis (TB) disease prevalence survey was undertaken amongst the Baiga primitive tribal community of Baiga Chak in central India. MATERIAL AND METHODS: A population of 2,359 was covered under the study. Sputum samples were collected from chest symptomatics and examined for smear microscopy and culture. RESULTS: Overall prevalence of PTB was 146 (95% C.I: 0-318) per 100,000 population. CONCLUSION: The findings suggest that TB is not a major public health problem amongst this tribal group. However, there is still the need to maintain and further strengthen TB control measures on a sustained and long term basis in the area.

Why do tuberculosis suspects bypass local services to attend tuberculosis sanatorium?

BACKGROUND: The Government Hospital of Thoracic Medicine (GHTM), Tambaram, in Kanchipuram district (formerly known as tuberculosis [TB] sanatorium), Tamil Nadu, draws patients from all over India although RNTCP services have been in place country-wide for a number of years. OBJECTIVE: To document the reasons for patients with chest symptoms attending GHTM, Tambaram. MATERIALS AND METHODS: In a prospective observational study, on a simple random sample basis, TB suspects attending the out-patient department of GHTM during the period January-March, 2006, were interviewed using a semi-structured interview schedule. Information on demographic, socio-economic characteristics and reasons for attending GHTM for health care was collected. RESULTS: A total of 2,023 respondents attended GHTM during the study period; 56% were males, 67% were aged <45 years, 63% were literates and the average annual family income was Rs 25,000. Multiple reasons for attending GHTM were given: popularity of the centre (82%), perceived availability of good treatment (52%), referral by earlier treated patients (36%), expectation of specialized care (22%), referred by treating physicians (13%), and came for inpatient care (11%). CONCLUSION: Despite the availability of local RNTCP health services, many patients with chest symptoms made use of GHTM services due to the reputation of the former "TB sanatorium" in the community. The findings suggest that there is a need to improve community awareness of the availability of free diagnostic and treatment facilities locally under RNTCP.

Prevalence of pulmonary tuberculosis among the Bharia, a primitive tribe of Madhya Pradesh, central India.

A cross-sectional survey was undertaken to estimate the prevalence of pulmonary tuberculosis (TB) among the primitive Bharia tribe of Madhya Pradesh, India. Virtually the entire community in Patalkot valley of Chhindwara District was covered. Individuals aged > or =15 years were questioned about chest symptoms relating to TB. Sputum samples were collected and examined by smear microscopy and culture. The overall prevalence of pulmonary TB was found to be 432 per 100 000 population-not dissimilar to that seen in the wider population in India. There is, however, an urgent need to strengthen TB services in the area to improve access for this group.

Assessment of X-ray readers in TB prevalence surveys.

A prevalence study was carried out a rural community in Tiruvallur district in Tami Nadu to standardize the method of assessing an X-ray reader in tuberculosis (TB) prevalence surveys by means of different measures of agreement between the reader and a Standard Reader (SR). The exercise on assessing the X-ray readers was carried out on two occasions; one involving three trainee readers (R1, R2, and R3), and the other involving one trainee reader (R4). The extent of agreement was estimated using Kappa statistics (K), over-diagnosis, under-diagnosis, crude agreement and prevalence adjusted bias adjusted kappa (PABAK). The overall performance of readers R1, R2, and R3 was not satisfactory in terms of K (21, 34 and 14%) in the first assessment. The K, over-diagnosis and under-diagnosis were estimated to be 61, 28 and 4% for R1, 63, 18 and 4% for R2 and 58, 31 and 5% for R3 in the final assessment. This suggested that R2 performed well compared to the other two readers. The K was 68% for R4 in the first assessment. As the over-diagnosis was to the extent of 40%, the trainee reader underwent one more assessment. The K was 64% which was as good as before, but there was no improvement in the over-diagnosis (43.5%) in the second assessment. Based on the performance, only one reader (R2) was certified as qualified for X-ray reading in the first occasion while the reader (R4) assessed in the second occasion was not qualified. These findings were subject to the inherent variation in the SR's readings against which the readers were assessed.