Contribution of medical colleges to tuberculosis control in India under the Revised National Tuberculosis Control Programme (RNTCP): lessons learnt & challenges ahead.

Medical college faculty, who are academicians are seldom directly involved in the implementation of national public health programmes. More than a decade ago for the first time in the global history of tuberculosis (TB) control, medical colleges of India were involved in the Revised National TB Control Programme (RNTCP) of Government of India (GOI). This report documents the unique and extraordinary course of events that led to the involvement of medical colleges in the RNTCP of GOI. It also reports the contributions made by the medical colleges to TB control in India. For more than a decade, medical colleges have been providing diagnostic services (Designated Microscopy Centres), treatment [Directly Observed Treatment (DOT) Centres] referral for treatment, recording and reporting data, carrying out advocacy for RNTCP and conducting operational research relevant to RNTCP. Medical colleges are contributing to diagnosis and treatment of human immunodeficiency virus (HIV)-TB co-infection and development of laboratory infrastructure for early diagnosis of multidrug-resistant and/or extensively drug-resistant TB (M/XDR-TB) and DOTS-Plus sites for treatment of MDR-TB cases. Overall, at a national level, medical colleges have contributed to 25 per cent of TB suspects referred for diagnosis; 23 per cent of 'new smear-positives' diagnosed; 7 per cent of DOT provision within medical college; and 86 per cent treatment success rate among new smear-positive patients. As the Programme widens its scope, future challenges include sustenance of this contribution and facilitating universal access to quality TB care; greater involvement in operational research relevant to the Programme needs; and better co-ordination mechanisms between district, state, zonal and national level to encourage their involvement.

Public health requirements for rapid progress in global health.

Effective public health interventions can save hundreds of millions of lives in developing countries, as well as create broad social and economic benefits. Unfortunately, public health approaches and solutions applied in developed countries are often assumed to be inappropriate or unattainable in developing countries. This has sometimes forestalled effective interventions in parts of the world where they are most needed, despite conditions that now facilitate lasting solutions to both long-standing and emerging global public health problems. Core public health functions are similar regardless of a country's income level. Although some resource-intensive approaches from industrialised nations are inappropriate in less developed countries, many basic public health measures achieved decades ago in developed countries are urgently needed, highly appropriate, extremely cost-effective and eminently attainable in developing countries today. About half of the disease burden in low and middle-income countries is now from non-communicable diseases, but non-communicable disease epidemics that will otherwise increase rapidly in the developing world can be avoided or reversed. Progress of public health in developing countries is possible, but will require sufficient funding and human resources; improved physical plant and information systems; effective programme implementation and regulatory capacity; and, most importantly, political will at the highest levels of government.

Lessons from tuberculosis control for public health.

Tuberculosis (TB) control in many ways exemplifies evidence-based public health practice, rigorously implemented, with appropriate emphasis on the central importance of political support for success. With more than 30 million patients treated in the past decade, TB control has important implications for managing both communicable and non-communicable diseases. Simple diagnostic tests, meticulously proven standardized treatment regimens with assured drug supply, supportive case management and a superb information system that tracks the progress of every patient, all facilitate effective program implementation. TB control shows that public health programs, including those that require long-term treatment in the primary care system, can be effective in poor countries; however, TB rates are heavily influenced by the social, environmental and epidemiologic context, emphasizing that treatment is not enough and that socio-economic factors may be more important determinants of epidemiologic trends than treatment programs. TB control is effective when it combines two essential components: a practical, implementable, proven technical package, and political commitment. Political commitment is also essential to implement other interventions that can improve health, including healthier air, water and food, as well as programs to prevent or reduce tobacco smoking, cardiovascular disease, cancer, obesity and other growing public health problems. By implementing evidence-based practices, ensuring operational excellence, using information systems that facilitate accountability and evaluation, and obtaining and maintaining political support, we can address the public health challenges of the twenty-first century.

Rapid decline in prevalence of pulmonary tuberculosis after DOTS implementation in a rural area of South India.

SETTING: Tiruvallur District in Tamilnadu, South India, where the World Health Organization-recommended DOTS strategy was implemented as a tuberculosis (TB) control measure in 1999. OBJECTIVE: To assess the epidemiological impact of the DOTS strategy on the prevalence of pulmonary tuberculosis (PTB). DESIGN: Surveys of PTB were undertaken on representative population samples aged > or =15 years (n = 83000-90000), before and at 2.5 and 5 years after the implementation of the DOTS strategy. The prevalence of PTB (smear-positive/culture-positive) was estimated. RESULTS: TB prevalence declined by about 50% in 5 years, from 609 to 311 per 100000 population for culture-positive TB and from 326 to 169/100000 for smear-positive TB. The annual rate of decline was 12.6% (95%CI 11.2-14.0) for culture-positive TB and 12.3% (95%CI 8.6-15.8) for smear-positive TB. The decline was similar at all ages and for both sexes. CONCLUSION: With an efficient case detection programme and the DOTS strategy, it is feasible to bring about a substantial reduction in the burden of TB in the community.

Active community surveillance of the impact of different tuberculosis control measures, Tiruvallur, South India, 1968-2001.

BACKGROUND: Tuberculosis is curable, but community surveys documenting epidemiological impact of the WHO-recommended DOTS strategy on tuberculosis prevalence have not been published. We used active community surveillance to compare the impact of DOTS with earlier programmes. METHODS: We conducted tuberculosis disease surveys using random cluster sampling of a rural population in South India approximately every 2.5 years from 1968 to 1986, using radiography as a screening tool for sputum examination. In 1999, DOTS was implemented in the area. Prevalence surveys using radiography and symptom screening were conducted at the start of DOTS implementation and after 2.5 years. RESULTS: From 1968 to 1999, culture-positive and smear-positive tuberculosis declined by 2.3 and 2.5% per annum compared with 11.9 and 5.6% after DOTS implementation. The 2.5 year period of DOTS implementation accounted for one-fourth of the decline in prevalence of culture-positive tuberculosis over 33 years. Multivariate analysis showed that prevalence of culture-positive tuberculosis decreased substantially (10.0% per annum, 95% CI: 2.8-16.6%) owing to DOTS after only slight declines related to temporal trends (2.1% annual decline, 95% CI: 1.1-3.2%) and short-course chemotherapy (1.5% annual decline, 95% CI: -9.7% to 11.5%). Under DOTS, the proportion of total cases identified through clinical care increased from 81 to 92%. CONCLUSIONS: Following DOTS implementation, prevalence of culture-positive tuberculosis decreased rapidly following a gradual decline for the previous 30 years. In the absence of a large HIV epidemic and with relatively low levels of rifampicin resistance, DOTS was associated with rapid reduction of tuberculosis prevalence.

Ensuring accountability: the contribution of the cohort review method to tuberculosis control in New York City.

SETTING: In 1993, the New York City (NYC) Bureau of Tuberculosis Control developed the cohort review process as a quality assurance method to track and improve patient outcomes. METHODS: The Bureau Director reviews every tuberculosis (TB) case quarterly in a multi-disciplinary staff meeting. In 2004 we also began collecting details on issues identified at cohort review to quantify how this process directly impacts TB control efforts. RESULTS: From 1992 to 2004, NYC TB cases decreased by 72.7% and treatment success rates significantly increased by 26.7%. Implementing the cohort review was key to improving case management, thus leading to these results. For the 1039 patients in 2004, 596 issues were identified among 424 patients; 55.0% were incorrect, unclear or unknown patient information, 13.8% were treatment issues, 12.4% were case management issues and 10.6% were incomplete contact investigations. Most (76.5%) issues were addressed within 30 days of the cohort reviews. CONCLUSION: A systematic review of every TB case improves the quality of patient information, enhances patient treatment and ensures accountability at all levels of the TB control program.

Value of dual testing for identifying tuberculous infection.

SETTING: A rural community in Chingleput district in Tamil Nadu state in south India. OBJECTIVE: To determine the value of dual testing with PPD-S and PPD-B for identifying subjects with a tuberculous infection. DESIGN: About 240,000 subjects in rural south India, all of whom were tested initially with PPD-S and PPD-B, were followed up for 15 years, mainly by total population survey once in every 212 years. The incidence of culture-positive tuberculosis was estimated using life-table technique. RESULTS: Among 17,530 subjects with an intermediate reaction (8-11 mm) to PPD-S at intake, 285 with an induration to PPD-S exceeding the induration to PPD-B by at least 2mm, had a significantly higher incidence of culture-positive tuberculosis than the remaining (154 and 93 per 100,000), and similarly 481 who had an induration of <10mm to PPD-B compared to those with >or=10 mm (131 and 93 per 100,000). These subjects may be regarded as having a tuberculous infection. Infection with non-tuberculous mycobacteria conferred protection of about 30% against the development of tuberculosis over a 15-year period. CONCLUSION: In subjects with an intermediate reaction (8-11 mm) to PPD-S, dual testing with PPD-B enabled identification of those with a tuberculous infection. Most of the reactions were due to non-tuberculous mycobacteria.

Improved tuberculosis case detection through public-private partnership and laboratory-based surveillance, Kannur District, Kerala, India, 2001-2002.

BACKGROUND: Efforts to intensify global tuberculosis (TB) control are limited by difficulties in coordinating with private doctors. More than half of Indian TB patients may initially consult a private provider, but many are neither diagnosed accurately nor treated effectively. We established and evaluated a public-private partnership based on surveillance of TB detected in private laboratories and use of standardised directly observed treatment regimens. METHODS: In one district, the governmental TB control programme offered training in microscopy to all large private sector laboratories, and educated private physicians on the importance of microscopy for TB diagnosis. We reviewed records from participating private laboratories and all publicly diagnosed patients. RESULTS: Of 2328 pulmonary TB patients registered from July 2001 to December 2002, 404 (17%) were detected in the private sector. The annual new AFB-positive case notification rate increased by 21%, from 27.8/100,000 in 2000 to 33.5/100,000 in 2002. Surveillance at private laboratories found an additional 260 nonregistered AFB-positive patients. CONCLUSIONS: This public-private partnership substantially increased TB case detection and established a sustainable framework for private sector involvement in TB control. In the setting of a strong public sector programme, the combination of active surveillance of private laboratories along with physician sensitisation is a promising approach to improve TB case detection.

Comparison of cough of 2 and 3 weeks to improve detection of smear-positive tuberculosis cases among out-patients in India.

SETTING: Governmental health facilities in six districts of India. OBJECTIVE: To estimate the prevalence of cough and to compare the detection of smear-positive tuberculosis (TB) among out-patients with cough of > or =2 or > or =3 weeks. DESIGN: Trained health workers questioned each out-patient for presence of cough. Those with cough > or =2 weeks underwent sputum microscopy. RESULTS: Of 55561 out-patients interviewed, 2210 (4%) had cough > or =2 weeks, of whom 267 had sputum-positive TB, compared to 182/1370 with cough > or =3 weeks. The 31% who did not spontaneously complain of cough were less likely to be sputum-positive than those who did (45/680 [7%] vs. 222/1530 [15%], P < 0.001), but they accounted for 45/267 smear-positive cases. Using cough > or =2 weeks as the screening criterion, the estimated number of smears performed per day at each primary and secondary health care facility was respectively 8 and 19, compared to 5 and 12 using cough > or =3 weeks. CONCLUSION: The detection of smear-positive TB cases can be substantially improved by actively eliciting history of cough from all out-patients, and by changing the screening criterion for performing sputum microscopy among out-patients from cough > or =3 weeks to > or =2 weeks. Before implementing this change nationally, its programmatic feasibility should be assessed.

A survey of tuberculosis hospitals in India.

SETTING: Hospitals with beds for tuberculosis (TB) in India. OBJECTIVES: To assess diagnostic and treatment practices at institutions offering secondary or tertiary level care for TB patients, and to determine the resources being used at these institutions. DESIGN: Countrywide cross-sectional survey of TB hospitals using a mailed semi-structured questionnaire sent to all 105 hospitals with 100 or more beds and to all State Directorate Health Services. RESULTS: The 94 hospitals that returned the questionnaire had 15773 TB beds, one third of the total TB beds in the country. Nearly 1 million patients sought treatment in the TB hospitals and one third were diagnosed with TB; the ratio of smear-positive to smear-negative patients was 1:2.7. Sixty-four per cent of hospitals prescribed unobserved rifampicin in the continuation phase, and 56% of sputum smear-positive patients were hospitalised. The annual expenditure for the TB hospitals was more than the total annual budget for the TB control programme of the country. CONCLUSIONS: In view of the high number of patients seen and the suboptimal practices observed, urgent steps should be taken to ensure implementation of correct diagnostic and treatment policies in hospitals with TB beds.

Reduced detection by Ziehl-Neelsen method of acid-fast bacilli in sputum samples preserved in cetylpyridinium chloride solution.

SETTING: Twelve health facilities implementing the DOTS strategy, and the Tuberculosis Research Centre (TRC), Chennai, India. OBJECTIVE: To determine the detection rates using Ziehl-Neelsen (ZN) and auramine-phenol to stain acid-fast bacilli (AFB) in sputum samples stored in cetylpyridinium chloride (CPC) solution. METHODS: Two smears were prepared from each of 988 sputum samples collected in CPC and randomly allocated, one to ZN and the other to auramine-phenol staining. All samples were processed for culture of Mycobacterium tuberculosis. RESULTS: A significantly higher proportion of samples were negative using the ZN method compared to the auramine-phenol method (74.5% vs. 61.8%, McNamara's paired chi2 test; P < 0.001). Among 377 samples that were positive using auramine-phenol, 44% were negative using ZN. There were more culture-positive, smear-negative samples in ZN (52.7%) than in auramine-phenol (30%); the difference attained statistical significance (McNemar's paired chi2 test; P < 0.00004). Using ZN, of the 104 smears made immediately after collection, 52 were positive for AFB, of which only 35 (67.3%) were positive after storage in CPC; the reduction in the number of positive smears attained statistical significance (McNemar's paired chi2 test; P = 0.004). CONCLUSION: Detection of AFB in sputum samples preserved in CPC is significantly reduced using ZN staining.

Gender disparities in tuberculosis: report from a rural DOTS programme in south India.

SETTING: Tiruvallur District, south India. OBJECTIVES: To examine gender differences in tuberculosis among adults aged >14 years with respect to infection and disease prevalence, health care service access, care seeking behaviour, diagnostic delay, convenience of directly observed treatment (DOT), stigma and treatment adherence. METHODS: Data were collected from 1) community survey, 2) self-referred out-patients seeking care at governmental primary health institutions (PHIs), 3) tuberculosis suspects referred for sputum microscopy at PHIs, and 4) tuberculosis patients notified under DOTS. Community survey results were compared with those for patients notified at PHIs. RESULTS: In the community, 66% of males and 57% of females had tuberculosis infection. The prevalence of smear-positive tuberculosis was 568 and 87/100,000, respectively, among males and females. Fewer males than females attended PHIs (68 men for every 100 women). Females constituted 13% of all smear-positive patients detected in the community survey, and 20% of those detected at PHIs (P < 0.05). The probability of notification decreased significantly with age among both males and females. Significantly more females than males felt inhibited discussing their illness with family (21% vs. 14%) and needed to be accompanied for DOT (11% vs. 6%). Males had twice the risk of treatment default than females (19% vs. 8%; P < 0.01). CONCLUSIONS: Despite facing greater stigma and inconvenience, women were more likely than men to access health services, be notified under DOTS and adhere to treatment. Men and elderly patients need additional support to access diagnostic and DOT services.

A baseline survey of the prevalence of tuberculosis in a community in south India at the commencement of a DOTS programme.

OBJECTIVE: To determine the baseline prevalence of culture-positive and smear-positive tuberculosis and the annual risk of tuberculous infection (ARTI) in a community in south India where DOTS is being implemented. METHODS: Using cluster sampling, 50 rural panchayats (villages) and three urban units in Tiruvallur district were selected randomly. All adults aged > or = 15 years underwent symptom and radiographic examination, and those with abnormal shadows and/or chest symptoms had sputum smear and culture examination. In another cluster sample of 73 villages and three urban units, all children aged < 10 years were tuberculin tested. RESULTS: The prevalence of culture-positive and smear-positive tuberculosis was respectively 605 and 323/100,000. Both increased appreciably with age, and were substantially higher in males than in females at all ages; the overall male:female ratio was 5.5 for culture-positive and 6.5 for smear-positive tuberculosis. The ARTI in children aged under 10 years was 1.6%, and was unaffected by sex. Over three decades there was an overall decline of 1.8% per annum in the prevalence of culture-positive and 2.1% for smear-positive tuberculosis. CONCLUSION: Tuberculosis is a major problem in this rural community in south India, with a prevalence of 605/100,000 for culture-positive tuberculosis and 323/100,000 for smear-positive tuberculosis.

Impact of national consultants on successful expansion of effective tuberculosis control in India.

SETTING: India, during a period of rapid expansion of DOTS services. DOTS expansion has been slow in many countries. OBJECTIVE: To document use of consultants to expand DOTS effectively. DESIGN: Staff were contracted to monitor DOTS expansion and implementation. To estimate the impact of these staff, we compared areas with and without consultants, and individual areas before and after consultants were assigned. Consultants were preferentially assigned to the more difficult areas; the temporary absence of consultants reflected non-availability of candidates. RESULTS: Areas with consultants met pre-defined criteria and began DOTS service delivery faster (median 9 vs. 18 months of preparation) than areas without consultants. Rates of sputum conversion (87% vs. 83%, P < 0.001) and treatment success (83% vs. 78%, P < 0.001) were significantly higher in areas with consultants present. CONCLUSION: Assignment of consultants resulted in much more rapid implementation of the DOTS strategy, and better quality performance. Continued effective performance in these areas will rely on many factors, but the need for consultants appears to be decreasing, suggesting that they have provided sustainable improvements. The effectiveness of local consultants may have important implications for efforts to scale up public health interventions for tuberculosis, malaria, AIDS and other diseases in developing countries.

Are community surveys to detect tuberculosis in high prevalence areas useful? Results of a comparative study from Tiruvallur District, South India.

BACKGROUND: In Tiruvallur District, South India, tuberculosis cases are detected at health facilities (HF) as part of a DOTS programme, and by screening adults through community survey (CS) as part of ongoing epidemiological research. OBJECTIVE: To compare socio-demographic, clinical and bacteriological characteristics and treatment outcomes of all patients detected at HF with those of all patients detected by CS during a 12-month period. RESULTS: Of 32,663 adults surveyed, 100 had smear-positive and 116 had smear-negative tuberculosis; of 65 smear-positive patients who began treatment, 44 were cured. Compared to HF patients, CS patients were significantly more likely to be older (AOR = 1.9), male (AOR = 2.7), non-literate (AOR = 1.7), and living in poor quality housing (AOR = 2.0), and were less likely to have cough >3 weeks (AOR = 3.4) or smear-positive tuberculosis (AOR = 4.2). Of 61 new smear-positive CS patients, 40 reported chest symptoms; of these, 32 (80%) had already consulted a health-care provider, but remained undiagnosed. CONCLUSIONS: The community survey was of little value in tuberculosis case detection even in this high-prevalence setting. Patients identified by the survey were less symptomatic and less infectious, and less than half were cured. Diagnostic services should be made more accessible to the elderly, the non-literate and men.

Risk factors associated with default, failure and death among tuberculosis patients treated in a DOTS programme in Tiruvallur District, South India, 2000.

OBJECTIVE: To identify risk factors associated with default, failure and death among tuberculosis patients treated in a newly implemented DOTS programme in South India. DESIGN: Analysis of all patients registered from May 1999 through April 2000. A community survey for active tuberculosis was underway in the area; patients identified in the community survey were also treated in this programme. RESULTS: In all, 676 patients were registered during the period of the study. Among new smear-positive patients (n = 295), 74% were cured, 17% defaulted, 5% died and 4% failed treatment. In multivariate analysis (n = 676), higher default rates were associated with irregular treatment (adjusted odds ratio [AOR] 4.3; 95%CI 2.5-7.4), being male (AOR 3.4; 95%CI 1.5-8.2), history of previous treatment (AOR 2.8; 95%CI 1.6-4.9), alcoholism (AOR 2.2; 95%CI 1.3-3.6), and diagnosis by community survey (AOR 2.1; 95%CI 1.2-3.6). Patients with multidrug-resistant tuberculosis (MDR-TB) were more likely to fail treatment (33% vs. 3%; P < 0.001). More than half of the patients receiving Category II treatment who remained sputum-positive after 3 or 4 months of treatment had MDR-TB, and a large proportion of these patients failed treatment. Higher death rates were independently associated with weight <35 kg (AOR 3.8; 95%CI 1.9-7.8) and history of previous treatment (AOR 3.3; 95%CI 1.5-7.0). CONCLUSIONS: During this first year of DOTS implementation with sub-optimal performance, high rates of default and death were responsible for low cure rates. Male patients and those with alcoholism were at increased risk of default, as were patients identified by community survey. To prevent default, directly observed treatment should be made more convenient for patients. To reduce mortality, the possible role of nutritional interventions should be explored among underweight patients.

Washing of new microscopic glass slides in dichromate solution does not influence sputum AFB smear results.

SETTING: Microscopy centres in Tiruvallur District, Tamil Nadu, India, implementing DOTS. OBJECTIVE: To know whether washing new glass slides in dichromate solution is essential for effective sputum acid-fast bacilli microscopy. METHODS: Two direct smears were prepared from each of 1750 sputum samples. One was made on dichromate solution-cleaned new glass slides and the other was made on unwashed new glass slides. The smears were blinded and examined. RESULTS: Of the 1750 specimens, 13.5% and 13.08% were positive for AFB using washed and unwashed slides, respectively (P = 0.12). The concordance between these two (including one grade above and one below) was 98.7%. CONCLUSION: Washing of new glass slides in dichromate solution is not essential for AFB microscopy.

Public-private partnership in tuberculosis control: experience in Hyderabad, India.

SETTING: Hyderabad, India. OBJECTIVE: To determine whether private practitioners and the government can collaborate with a nongovernmental intermediary to implement DOTS effectively. DESIGN: A non-profit hospital provided DOTS services to a population of 100000 for 3 years, then expanded coverage to 500000 in October 1998. A hospital physician visited all private practitioners, encouraged them to refer patients, and gave feedback on each patient referred. After diagnosis, patients received directly observed treatment free of charge at the trust hospital or at 30 conveniently located small hospitals operated by local private practitioners. No financial incentives were used to encourage physicians to refer patients or to provide treatment observation. Diagnosis, treatment, and case and outcome definitions were performed as per DOTS policies; medicines and laboratory reagents were provided by the government. RESULTS: All 244 allopathic and 114 non-allopathic physicians practising in the area agreed to participate; 59% referred at least one patient. Of 2244 persons referred, 969 (43%) had tuberculosis. Physicians had obtained chest radiographs on 80% of patients before referral for sputum microscopy. The detection rate increased from 50 to 200/100000 over the first 2-3 years of the project, and has increased gradually since expansion; 90% of new smear-positive patients and 77% of re-treatment patients were successfully treated. Compared with those treated at a neighbouring government DOTS centre, patients in this project paid less for diagnosis ($5 vs. $20) and treatment ($1 vs. $11), largely due to lower transport costs. CONCLUSIONS: Collaborative efforts between private practitioners and the government can achieve moderate-high rates of case detection and high rates of treatment success. Public-private services appeared to be more convenient to patients, who paid less for care and were less likely to miss work in order to participate in DOTS. Clearly defined roles and expectations and frequent communication are essential to success. An institution such as a non-profit hospital can serve as an effective intermediary between the government DOTS programme and private practitioners.

TB prevention in HIV clinics in New York City.

SETTING: Ten hospital-based human immunodeficiency virus (HIV) clinics in New York City. OBJECTIVE: To evaluate tuberculosis (TB) prevention in HIV clinics based on the prevalence and incidence of TB and the efficacy of preventive therapy with isoniazid (INH). DESIGN: The medical records of 2393 HIV-infected patients with a first clinic visit in 1995 were reviewed retrospectively. Deaths and TB cases through December 1997 were ascertained through a match with the TB and AIDS registries. RESULTS: At first visit, 92 patients (4%) had a history of TB, 98 (4%) were being treated for TB, and six (<1%) were diagnosed with TB. During follow-up, 23 cases were diagnosed, an incidence of 0.53 per 100 person-years (py) (95%CI 0.34-0.77). Among 439 tuberculin skin test (TST) positive patients, the incidence of TB/100 py was 1.63 (95%CI 0.27-5.02) in patients with no INH, 1.28 (95%CI 0.40-2.98) in patients with <12 months of INH, and 1.06 (95%CI 0.38-2.28) in patients with 12 months of INH. The incidence/100 py was 0.0 (95%CI 0.0-0.78) in TST-negative patients and 0.37 (95%CI 0.09-0.95) in anergic patients. The relative risk of TB was 0.65 (95%CI 0.14-4.56) in TST-positive patients with 12 months of INH (vs. none). CONCLUSIONS: The benefits of TB prevention efforts in these HIV clinics from 1995 to 1997 were limited because most TB occurred before the first clinic visit. Methods for reaching HIV-infected patients earlier should be identified.

Trends in the prevalence and incidence of tuberculosis in south India.

OBJECTIVE: To study trends in the prevalence and incidence of tuberculosis in south India. METHODS: In 1968-1970, about 100,000 subjects were surveyed for tuberculosis and followed thereafter for 15 years, mainly by repeat survey once every 2.5 years. New entrants were inducted at every repeat survey. Radiographic examination of subjects aged 5 years or more and sputum smear and culture examinations of those with an abnormal shadow were undertaken; tuberculin tests were done initially on all, and at 4, 10 and 15 years in selected samples of those aged 1-9 years. RESULTS: The prevalence of culture-positive tuberculosis decreased by 1.4% per annum to 694/100,000, while that of smear-positive tuberculosis showed no significant decrease from 457/100,000. The annual incidence of culture-positive tuberculosis decreased by 4.3%/annum to 189/100,000 and that of smear-positive tuberculosis decreased by 2.3%/annum to 113/100,000. Decreases in incidence occurred exclusively in those with abnormal radiographic findings suggestive of tuberculosis at the start of the period. The annual risk of tuberculosis infection (ARTI) was initially 2%, and showed no sign of decline over the period. CONCLUSION: The prevalence of tuberculosis and ARTI showed little or no decrease over the 15-year period. A significant decrease in incidence occurred, but exclusively in those with abnormal radiograph suggestive of tuberculosis at the start of the period.