Annual risk of tuberculosis infection in a rural population of South India and its relationship with prevalence of smear positive pulmonary tuberculosis.

Background: We conducted a tuberculin survey to estimate the annual risk of tuberculous infection (ARTI) among children in a sub-division of rural Bangalore district. A TB disease survey was conducted in the same area around the same time and has already been published. DOTS strategy is being implemented in the study area since 2002. Methods: The tuberculin survey was conducted during 2010-2011 among 3838, 5-9-year-old children attending 147 schools selected by simple random sampling. Children were tuberculin tested with 2TU PPD RT23 with Tween 80 and maximum diameter of induration was measured between 48-96 hours. ARTI was computed from prevalence of infection estimated by mirror-image technique. Prevalence of smear positive pulmonary TB estimated during the disease prevalence survey in 2008-10 was used to find out its relationship with ARTI. Results: Using the observed mode of tuberculin reaction sizes at 19 mm, among surveyed children, prevalence of infection was estimated at 7.3% (CI: 6.5-8.1); ARTI was computed at 1.05%. Considering the mean age of children, estimated ARTI most closely approximated to the year 2008. Every one per cent ARTI was found to correspond to a prevalence of 103 sputum smear positive patients of PTB, which was similar to the ratio of 106 found in the same study area during 1960s. Conclusion: There has been no change in the relationship between ARTI and prevalence of smear positive pulmonary TB from the pre-DOTS era and thus in the number of children infected by each adult point prevalent case of smear positive pulmonary TB each year suggesting the need for early case detection and treatment.

Relationship of nutritional status with tuberculin sensitivity.

Objective. To estimate the prevalence of under- nutrition among school children and to find out the relationship between nutritional status and tuberculin sensitivity. Methods. A cross sectional study was carried out among 3335 children between 5-8 years of age, attending 60 schools in Bangalore city, selected by stratified random sampling. The nutritional anthropometric indices were calculated using reference median as recommended by World Health Organization, classified according to standard deviation units termed as Z-scores. The nutritional status of the children was assessed by weight for age, height for age and bio-mass-index (BMI). Results. Depending upon the method for classifying nutritional status, the prevalence of under-nutrition (including mild and severe under-nutrition) varied between 14.9-29.8%. The prevalence of severe under-nutrition varied from 2.9-6.7%. The frequency distributions of reaction sizes to tuberculin were found to be similar among children classified by nutritional status. The differences in proportions of significant reactions (≥10mm) and mean tuberculin reaction sizes between children classified by nutritional status were not found to be statistically significant. Conclusion. Tuberculin sensitivity was not influenced by nutritional status among apparently healthy school children.

Utilization of RNTCP services in rural areas of Bellary District, Karnataka, by gender, age and distance from health centre.

Background: Knowledge on utilization pattern of RNTCP shall provide important inputs towards its strengthening in rural areas. Aims: To find out the utilization of RNTCP services by age, sex and distance from residence to designated microscopy centres and treating health centres. Methods: The study was carried out in Sandur TU of Bellary District, Karnataka. Information on age, sex and residence of persons with pulmonary symptoms and detected new sputum smear positive cases during third quarter 2003 to second quarter 2004; and their treatment outcome was obtained from the respective RNTCP records. Age and sex distribution of out-patients was collected from OPD registers of one randomly selected DMC and its PHCs. Results: A lesser number of males accessed the health care services. However, larger number of males with pulmonary symptoms and new sputum smear positive cases utilized RNTCP services than females in the ratio of 1.6:1 and 2.5:1 respectively. This was due to higher prevalence of persons with pulmonary symptoms and sputum positivity rate among males. Sputum positivity rates were also lower among the elderly. Male symptomatics and cases were on an average older than females. About 70% symptomatics and 53% cases resided at more than four kilometers from the respective DMCs and treating health centres. Treatment outcome was poorer among males with higher proportion of initial defaulters and among those residing at more than 20 kms. Conclusion: There is need to make health services available to the male working population at convenient hours and to be more vigilant to screen persons with pulmonary symptoms among the elderly. Collection of sputum specimen from eligible persons may be undertaken at PHCs which may later be transported to DMC. Supervision and motivation of treatment for male TB cases and those residing more than 20 kms from the treating health centres requires to be strengthened.

Prevalence of tuberculous infection among school children in Kerala.

BACKGROUND: There is paucity of information on epidemiological situation of Tuberculosis (TB) in the State of Kerala. The DOTS strategy under the Revised National Tuberculosis Control Programme (RNTCP) was introduced in the year 1998 to cover the entire State by 2002. OBJECTIVE: To estimate the prevalence of tuberculous infection among children attending 1-4th standard in a sample of selected schools in Kerala. METHODS: A cluster-sample school-based tuberculin survey was carried out in 70 schools selected by a two-stage sampling procedure. A total of 4821 children (including those with and without BCG scar) in the age group of 5-9 years were tuberculin tested using 1 TU PPD RT23 with Tween 80 and the maximum transverse diameter of induration was measured about 72 hours later. About 81% of the children were found to have BCG scars. Analysis was also undertaken by mixture model. RESULTS: While 67% of children without BCG scar and 62% with scar did not elicit any induration at the test site, the mode or anti-mode of reactions due to infection with tubercle bacilli could not be identified from the distribution graphs. Analysis by mixture model also did not provide the best fit thus precluding estimation of prevalence of infection. About 5% of children had reactions > or =10 mm, 3% had reactions > or =12 mm and 2% had reactions > or =14 mm. CONCLUSION: Low proportion of reactors indicated a low level of transmission of infection in Kerala. Considering the problems in interpretation of tuberculin survey data, it may not be feasible to use ARTI as an epidemiological parameter to monitor future trends of TB situation in the state.

Annual risk of tuberculous infection in Andhra Pradesh, India.

BACKGROUND: There is paucity of information on epidemiological situation of Tuberculosis (TB) in Andhra Pradesh. The DOTS strategy under the Revised National Tuberculosis Control Programme (RNTCP) was introduced in the year 2000 to cover the entire State by 2005. OBJECTIVES: To estimate the prevalence of tuberculous infection among children 5-9 years of age and to compute the average Annual Risk of Tuberculosis Infection (ARTI) from the estimated prevalence. METHODS: A cluster-sample house-based tuberculin survey was carried out in a representative sample of children between 5-9 years of age. The clusters were selected by a two-stage sampling procedure. At first stage, five districts were selected by probability proportional to population size (PPS) method. Depending upon child population ratio, 32 clusters allocated to each district were further sub-divided into rural and urban clusters selected by simple random sampling. A total of 3636 children, irrespective of their BCG scar status, were tuberculin tested using one TU PPD RT23 with Tween 80 and the maximum transverse diameter of induration was measured about 72 hours later. RESULTS: The prevalence of infection estimated by mirror-image technique using observed mode of reactions attributable to infection with tubercle bacilli at 20mm was 9.6% (95% CI: 8.0-11.2). The ARTI was computed at 1.4% (95% CI: 1.1-1.6). CONCLUSION: Survey findings indicate a fairly high rate of transmission of tubercle bacilli.

Tuberculin sensitivity among children vaccinated with BCG under universal immunization programme.

A tuberculin survey was conducted among 45988 children with BCG scar and 54227 children without BCG scar between 1-9 years of age and residing in selected rural areas of three defined zones of India. About 45-60% of the BCG-vaccinated children elicited reactions < 5 mm in size and about 70-80% had reactions < 10 mm. Therefore, in the majority of children (showing tuberculin reaction of < 10 mm), BCG-induced tuberculin sensitivity does not interfere with interpretation of tuberculin test. The study also revealed that a proportion of reactions among BCG vaccinated children in 5-9 mm, 10-14 mm and 15-19 mm range may be attributable to BCG vaccination. Therefore, reactions between 10-14 mm and especially 15-19 mm among the vaccinated children must be interpreted carefully. However, 19 mm was observed as the upper limit for BCG induced tuberculin sensitivity and all reactions >- 20 mm in size may be considered to be due to infection with tubercle bacilli, irrespective of the BCG vaccination status.

Protective effect of BCG among children vaccinated under universal immunization programme.

A case-control study was conducted to estimate the protective effect of BCG vaccination against tuberculosis among children. The children with suspicion of tuberculosis (TB) attending two hospitals in Bangalore city were registered into the study and subjected to detailed clinical examination and investigations. The presence of BCG scar was taken as evidence of vaccination. Modified Stegen-Jones scoring method was adopted for diagnosing TB. The hospital children with score of 7 were considered as TB cases. Children residing in the neighbourhood of cases were similarly investigated and those scoring 4 were labeled as controls. A total of 118 age-sex matched case-control pairs were identified and final analysis was confined to 113 cases and 109 controls after excluding children with doubtful BCG scar. A low protective effect of BCG vaccination at 31% (not significant, statistically) was observed against TB - all forms combined, among children vaccinated as under Universal Immunization Programme. Though the protective efficacy against extra-pulmonary TB was observed to be higher than for pulmonary TB, it was also not significant, statistically. It will be appropriate to conduct further studies on protection rendered by BCG vaccination against tuberculous meningitis and other severe forms of TB. Besides, the quality of vaccination programme including cold chain maintenance also needs to be evaluated.

Annual risk of tuberculous infection in rural areasof Kota district.

Background: A nation wide tuberculin study was undertaken to estimate the Annual Risk of Tuberculous Infection (ARTI) in different parts of India. The study in the rural areas of Kota, one of the districts selected for the survey, is described in this article. Material & Methods: A total of 6264 children 1-9 years of age, residing in 64 clusters were registered into the study. The children were subjected to the standard tuberculin test using 1 TU PPD RT23 with Tween 80 procured from BCG Laboratory, Guindy and the maximum transverse diameter of the induration was measured at about 72 hours. Results: A total of 3157 children without BCG scar and 1520 with BCG scar was successfully test read. The prevalence of infection among children without BCG scar using the mirror image technique was estimated as 13.6% and the ARTI was computed at 2.6%. Using similar technique, the prevalence of infection among the entire study group-irrespective of BCG scar was estimated as 14.9% and the ARTI was computed at 2.8%. Conclusion: The findings indicate a high rate of transmission of tuberculous infection in rural areas of Kota and emphasise the need for further strengthening of tuberculosis control measures.

Annual risk of tuberculous infection in Khammam a tribal district of Andhra Pradesh.

A tuberculin survey to estimate annual risk of tuberculosis was conducted in Khammam tribal district during 2001-2002. A total of 8637 children were test-read--2991 without BCG scar and 5442 with BCG scar. The tests were performed using ITU PPD RT23 and the maximum size of induration was recorded at about 72 hours after the test. Based on the frequency distribution of reaction size, cut-off point for infection with tubercle bacilli was considered at 12 mm. Using this criterion, the prevalence of infection was estimated at 11.8% among children without BCG scar and 10.6% among children with BCG scar. This difference was found to be statistically insignificant. ARTI rates computed from the prevalence estimates among children without and with BCG scar were 1.6% and 1.5% respectively. It was computed as 1.5% from the prevalence in the combined group i.e. irrespective of BCG scar status.

Hair loss in cancer chemotherapeutic patients.

The hair loss in 8 cancer patients aged between 18 and 60 years on chemotherapy was studied. All had diffuse moderate alopecia within 1 month of starting treatment. Of the 8, 3 had only telogen hairs and 3 had high dystrophic hair count. Both anagen and telogen effluvium are implicated.

Epidemiological situation of tuberculosis in India.

Epidemiological information on tuberculosis (TB) is vital for planning the control strategies in addition assessing the impact of intervention programmes. The survey findings by ICMR revealed the prevalence of sputum positive pulmonary TB is about 4 per 1000 population and an estimated 1.5 million infectious cases spreading infection in the community. Studies conducted by the National Tuberculosis Institute, Bangalore revealed similar diseases prevalence of sputum positive pulmonary TB. The annual risk of tuberculous infections defined as the probability of acquiring new infection with tubercle bacilli over a period of one year is the key parameter for the epidemiological study in developing countries. It is estimated that there are about 4.6 lakhs death in the country every year with one person dying every minute. The average annual risk of tuberculous infection is about 1.7%. The prospects of decreasing TB case now look good provided that all TB cases have access to the DOTS strategy by bringing the remaining uncovered half of the population under RNTCP.

Annual risk of tuberculous infection in rural areas of Junagadh district.

Paucity of epidemiological data on tuberculosis in India prompted the National Tuberculosis Institute, Bangalore to embark upon a nation-wide survey to estimate the Annual Risk of Tuberculosis Infection in different parts of the country. The survey in Junagadh district, one of the 26 districts drafted under the nation-wide survey is reported here. The prevalence of infection from the analysis of 3164 children not displaying scars of the BCG vaccination was 4.16% (CI: 3.17-5.14) and from this data the ARI was computed as 0.73% (CI: 0.55-0.91). The inclusion of vaccinated children into the study group yielded similar results. The estimate of the ARI in Junagadh district is lesser than that in several other parts of India which is probably in consonance with its better socio-economic development.

Tuberculin test.

Although tuberculin test is widely used for detection of tuberculous infection among children, there is no clear understanding about its performance and interpretation. This article has been written with the purpose of elucidating the performance and interpretation of standard tuberculin test, based on the experiences gained at the National Tuberculosis Institute, Bangalore and other centres. The standard tuberculin test involves intradermal injection of '1TU PPD RT23 with Tween 80' on the mid-volar aspect of forearm and measurement of the maximum transverse diameter of induration after 3 days. Larger the size of induration, higher is the probability of it being due to tuberculous infection. The majority of reactions with induration size of 15 mm and above are attributable to infection with tubercle bacilli, irrespective of BCG-vaccination status. While indurations of less than 5 mm indicate absence of any kind of tuberculin sensitivity, the majority of indurations in 5-9 mm range are usually of non-tuberculous nature. An induration of 10-14 mm requires more careful interpretation. It is more likely to be attributable to infection with tubercle bacilli in case of history of contact with smear positive case or among children with clinical findings of tuberculosis. However, the size of induration in an infected child may be diminished in the presence of immuno-suppressive conditions. One should also consider the purpose of the test while interpreting the test results.

Periventricular hemorrhage in term newborns originating from germinal matrix.

Six term newborns, presenting with seizures, in whom cranial sonogram showed isolated periventricular hemorrhage (SEH) are described. Age of onset of seizures ranged from day one of birth to day twenty-one. Seizures appeared spontaneously in previously healthy newborns in three cases. All but one survived, and three have near normal development. Isolation of hemorrhage to the periventricular area suggests germinal matrix to be the source of hemorrhage in these cases. These cases also emphasize the need to consider diagnosis of IVH in term-newborns presenting with seizures.