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.

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.

Impact of advocacy on the tuberculosis management practices of private practitioners in Chennai City, India.

BACKGROUND: Innovative schemes to ensure the participation of private practitioners (PPs) in the Revised National Tuberculosis Control Programme (RNTCP) are necessary to identify and treat all patients with tuberculosis (TB). We developed a novel public-private mix (PPM) model to encourage PPs to practise DOTS and participate in the RNTCP while retaining their patients. METHODS: The Resource Group for Education and Advocacy for Community Health (REACH) developed and implemented the programme in partnership with the Chennai local health authority and the Tuberculosis Research Centre, Chennai, India. PPs were sensitised to the RNTCP and DOTS through a one-to-one approach or group meetings, and were assisted in referring patients. Surveys were carried out at baseline and at the completion of the study to assess changes in attitudes and practices. RESULTS: Six hundred PPs underwent sensitisation about the RNTCP, after which the proportion of PPs adopting DOTS increased significantly (P < 0.001), and the majority (72.8%) used sputum testing for diagnosing TB. The proportion of PPs who used X-ray alone for diagnosis declined to 16.0% from a baseline of 45.4%. CONCLUSIONS: This PPM model, which emphasises sustained advocacy for DOTS and allows PPs to retain private patients, looks promising and needs to be tested at other sites.

DOTS reaches socially marginalized population in the community: a study from a rural area of South India.

We report here that the Directly Observed Treatment, Short course (DOTS) is reaching all tuberculosis patients in the community irrespective of social classification based on the analysis from the tuberculosis prevalence survey and programme performance during 1999-2003 from a rural area in Tamilnadu, South India. New smear- positive cases treated under a DOTS programme were classified in two groups namely; scheduled caste living in colony and other population. The prevalence of smear- positive cases among the scheduled caste population was 1.9 times higher than the other population and this was reflected in the notification also. The successful treatment outcome was also similar in these two groups (75% and 78% respectively; overall 77%). From these findings it is concluded that people living in colony have equal access to DOTS as those in the village.

Measuring tuberculosis burden, trends, and the impact of control programmes.

The targets for tuberculosis control, framed within the United Nations' Millennium Development Goals, are to ensure that the incidence per head of tuberculosis is falling by 2015, and that the 1990 prevalence and mortality per head are halved by 2015. In monitoring progress in tuberculosis control, the ultimate aim for all countries is to count tuberculosis cases (incidence) accurately through routine surveillance. Disease prevalence surveys are costly and laborious, but give unbiased measures of tuberculosis burden and trends, and are justified in high-burden countries where many cases and deaths are missed by surveillance systems. Most countries in which tuberculosis is highly endemic do not yet have reliable death registration systems. Verbal autopsy, used in cause-of-death surveys, is an alternative, interim method of assessing tuberculosis mortality, but needs further validation. Although several new assays for Mycobacterium tuberculosis infection have recently been devised, the tuberculin skin test remains the only practical method of measuring infection in populations. However, this test typically has low specificity and is therefore best used comparatively to assess geographical and temporal variation in risk of infection. By 2015, every country should be able to assess progress in tuberculosis control by estimating the time trend in incidence, and the magnitude of reductions in either prevalence or deaths.

Annual risk of tuberculosis infection among tribal population of central India.

OBJECTIVE: To estimate the annual risk of tuberculosis infection (ARTI) among tribal children of Madhya Pradesh, central India. METHODS: Community-based, cross-sectional tuberculin survey among children aged 1-9 years in the tribal population of Madhya Pradesh. Multistage stratified cluster sampling was used to select a representative random sample of villages predominated by tribal population from selected districts. A total of 4802 children were tuberculin-tested with 1TU of PPD RT 23 and the reaction sizes read after 72 h. RESULTS: A total of 3062 (64%) children had no BCG scar. The frequency distribution of children by reaction sizes indicated a fair mode at 18 mm in the right hand side of the distribution. By mirror-image technique, the prevalence of infection among children with no recognizable BCG scar was estimated as 6.8% (95% CI: 4.8-8.9%). The ARTI was computed as 1.3% (0.9-1.7%). The corresponding figures for children irrespective of scar status were 7.1% (95% CI: 5.5-8.8%) and 1.3% (1.0-1.7%) respectively. CONCLUSIONS: The risk of tuberculosis infection in tribal population of Madhya Pradesh, central India is not different from other areas of the country. There is, however, a need to further intensify tuberculosis control measures on a sustained and long-term basis.

The design effect and cluster samples: optimising tuberculosis prevalence surveys.

Cross-sectional surveys of disease prevalence, including for tuberculosis (TB), often use a two (or more) stage sampling procedure. By choosing clusters of people randomly from all possible clusters, the logistic costs of doing the survey can be reduced. However, this increases the statistical uncertainty in the estimate of prevalence, and we need to balance the reduction in cost against the increase in uncertainty. Here we describe cluster sampling and consider ways to determine the optimal survey design as well as the extent to which deviations from the optimal design matter. We illustrate the results using data from a recent survey in Cambodia in which TB was diagnosed using sputum smears, cultures and X-rays.

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.

Tuberculosis prevalence surveys: rationale and cost.

This article is the first of the educational series 'Assessing tuberculosis (TB) prevalence through population-based surveys'. The series will give overall guidance in conducting cross-sectional surveys of pulmonary TB (PTB) disease. TB prevalence surveys are most valuable in areas where notification data obtained through routine surveillance are of unproven accuracy or incomplete, and in areas with an estimated prevalence of bacteriologically confirmed TB of more than 100 per 100,000 population. To embark on a TB prevalence survey requires commitment from the national TB programme, compliance in the study population, plus availability of trained staff and financial resources. The primary objective of TB prevalence surveys is to determine the prevalence of PTB in the general population aged >or=15 years. Limitations of TB prevalence surveys are their inability to assess regional or geographic differences in prevalence of TB, estimate the burden of childhood TB or estimate the prevalence of extra-pulmonary TB. The cost of a prevalence survey is typically US$ 4-15 per person surveyed, and up to US$ 25 per person with radiographic screening. A survey of 50,000 people, of limited precision, would typically cost US$ 200,000-1,250,000.

Tuberculous infection in Saharia, a primitive tribal community of Central India.

A cross-sectional tuberculin survey was carried out to estimate the prevalence of tuberculous infection and the annual risk of tuberculosis infection (ARTI) among children of Saharia, a primitive ethnic group in Madhya Pradesh, Central India. A total of 1341 children aged 1-9 years were subjected to tuberculin testing with 1 TU of PPD RT 23 and the reaction sizes were read after 72 h. The proportion of BCG scar-positive children was 34.6%. The frequency distribution of children by reaction sizes indicated a clear-cut anti-mode at 11 mm and a mode at 18 mm at the right-hand side of the distribution. The prevalence of infection among children irrespective of BCG scar was estimated as 20.4% (95% CI 18.2-22.5%) and the ARTI was 3.9% (95% CI 3.5-4.3%). The corresponding figures were 21.1% (95% CI 18.3-23.8%) and 3.9% (95% CI 3.4-4.5%) among BCG scar-negative children and 19.0% (95% CI 15.4-22.5%) and 4.0% (95% CI 3.2-4.8%) among BCG scar-positive children. The findings of the present study show a high prevalence of tuberculous infection and high ARTI in this primitive ethnic group. There is an urgent need to further intensify tuberculosis control measures on a sustained and long-term basis in this area.

Pot method for storage & detection of acid-fast bacilli from sputum samples.

BACKGROUND & OBJECTIVES: Sputum acid-fast bacilli (AFB) microscopy services are not available in all health facilities. Alternative procedures are needed to transport sputum samples to the diagnostic centres for detection of AFB. The objective of the present study was to evaluate sputum smears made by pot-method with the direct smears made immediately after sputum collection by Ziehl-Neelsen (ZN) method. METHODS: Ninety three sputum samples from 49 pulmonary tuberculosis suspects were studied. Their direct smears (ZN smears) were stained by hot ZN method. The samples were then mixed with phenol ammonium sulphate basic fuchsin solution and stored at ambient conditions. The smears (pot smears), made on day 7, were then, decolourized and counter-stained for detection of AFB (pot method). The ZN and pot smears were read blind. After excluding 18 samples for various reasons, the results of pot and ZN smears of 63 samples from smear positive (2 of 3 direct smears were positive) and 12 from smear negative (3 of 3 direct smears were negative) patients were analysed. ZN method was the gold standard. RESULTS: Pot and ZN smears were positive in 61 of 63 samples from smear-positive patients and negative in 11 of 12 smear-negative patients (kappa = 0.87). The sensitivity and specificity of pot method were 96.8 and 91.7 per cent respectively. INTERPRETATION & CONCLUSION: Sputum samples can be stored for up to seven days in the sputum container with phenol ammonium sulphate basic fuchsin solution. However, a comprehensive study needs to be done confirm the accuracy of the pot method for storage and transportation of sputum to microscopy centres for detection of AFB.

Phenol ammonium sulphate basic fuchsin staining of sputum in pot for the detection of acid-fast bacilli.

BACKGROUND & OBJECTIVES: Improper practices of making direct smears of sputum for detection of acid-fast bacilli (AFB) and of disposing sputum cups are hazardous. The present study was undertaken with the objective to stain sputum samples in their containers by 'phenol (10%) ammonium sulphate (4%) basic fuchsin (2%) solution' and to decolourize and counterstain their smears for detection of AFB- (henceforth called pot method) and to compare the smear results of pot method with the standard Ziehl-Neelsen (ZN) method. METHODS: A total of 575 selected sputum samples from pulmonary tuberculosis patients were stained by the standard ZN and pot methods and the proportions of AFB positive smears were compared. RESULTS: Of the 575 samples, 126 were AFB positive for both the staining methods and the difference was not statistically significant. Pot method missed 9 ZN positive smears (8 scanty and one 1+) and ZN method missed 9 pot positive smears (9 scanty) and the difference was not significant. High grade smears (3+) were seen more in pot method (42) than in ZN method (25) and the difference was significant. INTERPRETATION & CONCLUSION: Our findings showed that pot method was comparable to standard ZN method and had many advantages. Pot method can be explored further for the detection of AFB in sputum samples obtained from pulmonary tuberculosis suspects.

DOTS reaches socially marginalized population in the community: a study from a rural area of South India.

We report here that the Directly Observed Treatment, Short course (DOTS) is reaching all tuberculosis patients in the community irrespective of social classification based on the analysis from the tuberculosis prevalence survey and programme performance during 1999-2003 from a rural area in Tamilnadu, South India. New smear- positive cases treated under a DOTS programme were classified in two groups namely; scheduled caste living in colony and other population. The prevalence of smear- positive cases among the scheduled caste population was 1.9 times higher than the other population and this was reflected in the notification also. The successful treatment outcome was also similar in these two groups (75% and 78% respectively; overall 77%). From these findings it is concluded that people living in colony have equal access to DOTS as those in the village.

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.

Selected biological and behavioural risk factors associated with pulmonary tuberculosis.

OBJECTIVES: To measure the independent association of risk factors age, sex, smoking and alcoholism with pulmonary tuberculosis (TB) in terms of prevalence odds ratio (POR). METHOD: A community-based cross-sectional survey was conducted from June 2001 to December 2003. A total of 93945 individuals aged > or = 15 years selected from a random sample of villages in a district from South India were screened for pulmonary TB by chest symptoms and chest X-ray (MMR). Two sputum samples were collected (one spot and one early morning) from patients with chest symptoms and those with abnormal X-rays for examination by microscopy for acid-fast bacilli and by culture for Mycobacterium tuberculosis. Bacillary cases are bacteriologically positive cases diagnosed by either sputum smear or culture examination. In addition, data on exposure to tobacco smoking and alcohol consumption were collected from the male population only. All females were considered non-smokers and non-alcoholics. RESULTS: A total of 429 bacteriologically positive cases were detected during the survey. The adjusted PORs (with 95%CI) for age, sex, smoking and alcoholism were 3.3 (2.7-4.1), 2.5 (1.9-3.3), 2.1 (1.7-2.7) and 1.5 (1.2-2.0), respectively. CONCLUSION: Risk factors such as age, sex, smoking and alcoholism are independently associated with pulmonary TB. Risk factors age and sex show a stronger association than smoking and alcoholism.

Evaluation of post-treatment health-related quality of life (HRQoL) among tuberculosis patients.

BACKGROUND: Health-related quality of life (HRQoL) measures the impact of a disease by assessing the health status of patients. OBJECTIVE: To assess the HRQoL of tuberculosis (TB) patients one year after treatment completion. METHODS: Patients registered under the TB control programme from July 2002 to June 2003 in a TB Unit in south India were interviewed one year after successful completion of treatment. Data on HRQoL were collected using the SF-36 questionnaire, which covers physical, mental and social well-being components. Data on economic well-being were also collected. Scores were given for all domains. RESULT: Of 436 TB patients interviewed, the mean scores for social, physical, mental and economic well-being were respectively 84, 74, 68 and 62 on a scale of 100. The well-being scores were significantly related to age, sex, education, employment and persistent symptoms. There was a significant association between economic and social well-being. CONCLUSION: This study suggests that the HRQoL of TB patients one year after successful completion of treatment under the TB control programme was normal for most of the domains studied and was associated with age, literacy and employment, income, smoking, alcoholism and persistence of symptoms.

Health-seeking behaviour of new smear-positive TB patients under a DOTS programme in Tamil Nadu, India, 2003.

BACKGROUND: Although case detection is above 70% in Tamil Nadu after DOTS implementation, an assessment of the timeliness of patient diagnosis and treatment is still needed. OBJECTIVE: To study the health-seeking behaviour of new smear-positive pulmonary tuberculosis (PTB) patients treated at government facilities. METHODS: New smear-positive patients diagnosed and treated between January and March 2003 in government facilities of randomly selected blocks in Tamil Nadu were interviewed using a semi-structured interview schedule. RESULTS: Of 601 patients interviewed, 65% contacted a provider within 28 days. The first contact was governmental for 47% and non-governmental for 53%. Median total, patient and provider delays were respectively 62, 28 and 28 days; provider delay was 9 days with government and 50 with private provider. In multivariate analysis, patient delay was significantly associated with smoking (P < 0.001) and mode of travel (P < 0.01), and provider delay with first consultation with a private provider (P < 0.001) and distance > 5 km from the health facility (P < 0.01). Twenty-five per cent of patients took more than two actions before diagnosis. CONCLUSION: Community awareness of TB needs to be increased. Greater private sector involvement in the Revised National Tuberculosis Control Programme is essential to reduce provider delay. Referral and sputum transportation to the diagnostic facility should be given priority.

The prevalence of tuberculosis in different economic strata: a community survey from South India.

A cross-sectional socio-economic survey to assess the standard of living index (SLI) of a rural population in South India was undertaken along with a tuberculosis (TB) prevalence survey during 2004-2006. Of 32,780 households, the SLI was low, medium and high in 22%, 36% and 42%, and TB prevalence was 343, 169 and 92 per 100,000 population, respectively, a significant decrease in trend (P < 0.001); 57% of the TB patients had a low SLI and the prevalence of TB was higher amongst the landless (P < 0.001), those living below the poverty line (P < 0.01) and in katcha houses (P < 0.001), suggesting that TB disproportionately affects those with a low SLI.

Coincident filarial, intestinal helminth, and mycobacterial infection: helminths fail to influence tuberculin reactivity, but BCG influences hookworm prevalence.

The prevalence of helminth and tuberculosis infections is high in South India, whereas Bacille-Calmette-Guerin (BCG) vaccine efficacy is low. Our aim was to determine whether concurrent helminth infection alters the ability to mount a delayed-type hypersensitivity response to tuberculin. In a cross-sectional study in southern India, individuals 6-65 years of age were screened for intestinal helminths, circulating filarial antigenemia, tuberculin reactivity, active tuberculosis, and history of BCG vaccination; 54% were purified protein derivative (PPD) positive, 32% had intestinal helminth infection, 9% were circulating filarial antigen positive, and 0.5% had culture-confirmed active tuberculosis. Only age and BCG vaccination were significantly associated with PPD reactivity; however, BCG vaccination was associated with a lower prevalence of hookworm infection relative to those without prior BCG vaccination. Neither intestinal helminth infection nor filarial infection was associated with diminished frequencies of PPD positivity. Our findings suggest that preceding helminth infection does not influence significantly the delayed-type hypersensitivity response to tuberculin.

Trend in the prevalence of TB infection and ARTI after implementation of a DOTS programme in south India.

OBJECTIVE: To estimate the risk of tuberculosis (TB) infection among children <10 years and assess the impact of a DOTS-based programme. SETTING: After DOTS implementation in Tiruvallur district, south India, we undertook three tuberculin surveys and estimated the ARTI among children aged <10 years. RESULTS: The ARTI estimates in the three tuberculin surveys were 1.6%, 1.4% and 1.2%, respectively. There was a significant decline in the trend of TB infection (P < 0.001). The annual decline estimated from the first to the third survey was 6%. CONCLUSION: DOTS implementation was associated with a substantial reduction in the risk of TB infection among children.