EPIDEMIOLOGY <<Back
 
 
001
TUBERCULIN SENSITIVITY IN YOUNG CHILDREN (0-4 YEARS OLD) AS AN INDEX OF TUBERCULOSIS IN THE COMMUNITY.
NL Bordia, Anton Geser, J Maclary, I Mundt & Kul Bhushan: Indian J TB 1960, 8, 25-43.

The purpose of this study was to find out whether the prevalence of infection in young children might be used as an index of the tuberculosis problem in a population. Tuberculin testing was done in a random sample of 2,883 children (0-4 years) in Bangalore city, of those 2,589 (89.8%) actually completed testing. A total of 4340 children were registered in 59 villages and of these 4090 (94.2%) were tuberculin tested. The villages were from Bangalore, Kolar and Mandya as these districts were within 100 miles from Bangalore city. The team went from house to house and made a complete registration of the children 0-4 years in the selected houses. Information on socio-economic status, density of population etc., was also collected before giving tuberculin 1 TU RT 23 with Tween 80.

The results of the study showed that prevalence of infection in 0-4 years age group of cantonment area was 1.6% and in the crowded city area 4.1% at 14mm induration level. In the rural population, the prevalence of tuberculosis infection was 2%. In the city, a positive correlation between tuberculosis infection and socio-economic condition was obtained while it was not seen in rural areas. It was not possible to establish any correlation between tuberculosis disease and infection either in rural or urban areas, as the population was not examined for the prevalence of tuberculosis disease.

KEY WORDS: PREVALENCE, INFECTION, CHILDREN, RURAL, URBAN, COMMUNITY.

003
RESURVEY OF 15 VILLAGES FROM THE MADANPALLE ZONE OF NATIONAL SAMPLE SURVEY ON TUBERCULOSIS
Raj Narain, MV Jambunathan & M Subramanian: Proceed Natl TB & Chest Diseases Workers’ Conf, Bangalore, 1962, 34-47.

A study was undertaken with the following objectives: (1) To estimate the proportion of population that would be available for resurvey after 5 years. (2) To ascertain five years later the fate of persons with X-ray pathology. (3) To compare the prevalence of tuberculosis in the villages at an interval of 5 years. Population of 15 of the 31 villages from the Madanapalle zone, was selected for this study. About 9,500 persons were registered and 7,200 were X-rayed at the initial survey. Five years later the same population was re-examined and nearly 70% were available for X-ray examination. Sputa were collected from persons with abnormal X-ray shadows interpreted as such by either of the two readers. Two spot samples were collected within an interval of 1-3 days and were examined by direct smear and by culture.

Analysis of the data shadow showed that: (1) There was no significant difference in the prevalence rates i.e., 3.6 and 4.6 per thousand respectively at two points of time. (2) During the interval, 30% of active cases had died and 20% were still active at the end of 5 years. (3) There was almost complete turn over of the bacillary cases during the 5 years interval.

KEY WORDS: RESURVEY, COVERAGE, PREVALENCE, MORBIDITY, MORTALITY.

006
SOME ASPECTS OF A TB PREVALENCE SURVEY IN A SOUTH INDIAN DISTRICT
Raj Narain, A Geser, MV Jambunathan & M Subramanian: Bull WHO 1963, 29, 641-64 & Indian J TB 1963, 9, 85-116.

The objective was to establish the prevalence rates for tuberculosis infection, radiologically active pulmonary tuberculosis and bacteriologically confirmed diseases for different age and sex groups. Tumkur District in Mysore State consisting of 2,392 villages, 10 towns of was selected for the study. The district headquarter town Tumkur was excluded from the survey. Random sample of 62 villages and 4 town blocks having a population of 34,746 persons constituted the study population. All the individuals available in the registered population were given a Mantoux test with 1 TU RT 23 with Tween 80. Longitudinal diameter of induration was read 3-4 days after the test. At the time of tuberculin test, all persons aged 10 years and above were offered a single 70mm photofluorogram. For each picture read as abnormal, a spot specimen of sputum of the individual concerned was collected at the time of reading the tuberculin test. Age and sex distribution of infection and disease were studied.

Various parameters concerning the prevalence of infection and disease in the community were reported. Prevalence rate of infection in all ages and both sexes of the population was found to be 38.3%, radiologically active tuberculosis 1.86% and 0.41% sputum positive disease. The infection and disease increased with age; of the total diseased, half were in age group 40 years and more and about 2/3 among males.

KEY WORDS: SURVEY, PREVALENCE, INFECTION, DISEASE, CASE, COMMIUNITY, RURAL, URBAN.

007
A COMPARISON OF THE RELATIVE VALUE OF SINGLE AND DOUBLE PICTURE TECHNIQUES IN TB PREVALANCE SURVEYS
Raj Narain, SS Nair & P Chandrasekhar: Indian J TB 1964, 11, 145-53.

Limitations of a single X-ray picture for locating and interpreting shadows in the chest had been studied earlier. In order to reduce these limitations, it was suggested that two pictures of each person be taken where the second picture was to be taken after a vertical displacement of X-ray tube, up or down by about 4 to 5cms. The advantages of taking two pictures simultaneously as compared to a single picture have not been studied so far. Two mobile X-ray units each with an odelca camera were alternated for the single and double picture examinations. A total of about 2,000 persons were X-rayed and were read independently by 3 readers. A spot sample of sputum was collected 3-4 days later from persons with abnormal X-ray shadows and was examined by direct smear microscopy.

Comparison of the readings of the two sets of pictures did not show a better agreement between different (inter- individual) readers or between two different readings of the same reader (intra-individual) when the two picture technique was used. The X-ray cases detected by double picture only by any one reader were not confirmed, more often than those detected by single picture only. The X-ray pictures of the bacillary cases were also not interpreted more often as active tuberculosis by the two picture technique. It was concluded that the double picture technique does not offer any advantage over the single picture technique.

KEY WORDS: SURVEY, PREVALENCE, X-RAY READING, X-RAY FILM, SINGLE PICTURE, DOUBLE PICTURE.

010
DISTRIBUTION OF INFECTION AND DISEASE AMONG HOUSEHOLDS IN A RURAL COMMUNITY
Raj Narain, SS Nair, G Ramanatha Rao & P Chandrasekhar: Bull WHO 1966, 34, 639-54 & Indian J TB 1966, 13, 129-46.

Studies on the distribution of tuberculous infection and disease in households have mostly been restricted to the examination of contacts of known cases. Clinical experience has lead to a strong belief that tuberculosis is a family disease and contact examination is a “must” for case-finding programmes. A representative picture of the distribution of infection and disease in households can be obtained only from a tuberculosis prevalence survey.

This paper reports an investigation, based on a prevalence survey in a rural community in south India. The survey techniques and study population have been described in an earlier report. Briefly, the defacto population was given a tuberculin test with 1 TU of PPD RT 23 with Tween 80 and those aged 10 years and above were examined by 70mm photofluorography. All the X-ray pictures were read by two independent readers. Those with any abnormal shadows by either of the two readers were eligible for examination of a single spot specimen of sputum by direct smear and culture. The defacto population numbered 29,813 and tuberculin test results were available for 27,115. After excluding BCG scars, the study population of 24,474 was distributed over 5,266 households which were further classified as “bacillary case household” with atleast one bacteriologically confirmed case, “X-ray case household” with atleast one radiologically active case but with no bacillary cases and ‘non-case household’ with neither a bacillary nor an X-ray case. Total bacillary cases were 77 and were distributed in 75 household. 74 households had one case each and one household had 3 bacillary cases.

The findings of the study have thrown considerable doubt on the usefulness of contact examination in tuberculosis control; (1) over 80% of the total number of infected persons, in any age group, occurred in households without cases, (2) cases of tuberculosis occurred mostly singly in households, and the chance of finding an additional case by contact examination in the same household is extremely small, (3) a common belief has been that prevalence of infection in children in 0-4 age group is a good index of disease in households, but in this study about 32% of households with cases of tuberculosis had no children in this age group, (4) in houses with bacteriologically confirmed case only 12% of the children in 0-4 age group showed evidence of infection, a possible explanation of such a low intensity of infection could be that there is resistance to infection. It is well known that some children even after repeated BCG vaccination do not become tuberculin positive. It is felt that a large number of children do inhale tubercle bacilli, but a primary complex does not develop or even if it develops, the children remain tuberculin negative. A hypothesis has been made that in addition to resistance to infection, there is something known as “resistance to disease”. Otherwise, it is difficult to explain why under conditions of heavy exposure in infection, only some individuals develop evidence of infection and very few develop disease thereafter.

KEY WORDS: PREVALENCE, INFECTION, DISEASE, CONTACT EXAMINATION, HOUSEHOLD, RURAL COMMUNITY.

011
FATE OF CASES DIAGNOSED IN A SURVEY
Raj Narain, G Ramanatha Rao, G Chandrasekhar & Pyare Lal: Proceed Natl TB & Chest Dis Workers’ Conf, Calcutta, 1966,72-78.

The report describes the changes that occurred during second survey carried out after an interval of one and half years in the cases diagnosed at the first survey done during 1961-62 from among a total population of about 62,000 in 119 villages in Bangalore District. It was observed that (1) Of the 62 sputum smear positive cases also having suggestive chest X-ray shadows, 34% had died, 35% were sputum positive and 31% had become culture negative after 1½ years. Of the 10 smear positive cases who were X-ray normal, non-e was culture positive at the start and 7 were negative by culture and smear after 1½ years. Of the 67 scanty smear positive cases (1 to 3 bacilli seen), only 3 were sputum positive, 10 were having X-ray shadows and half were tuberculin negative after 1½ years. (2) Of the 88 culture only positive cases (20 or more colonies and with X-ray evidence of disease) 31% had died and 47% continued to be sputum positive after 1½ years. A much smaller proportion of these changes occurred among culture positive cases with less than 20 colonies. (3) There were 457 persons having radiologically active tuberculosis on the basis of interpretation of a single X-ray picture by two independent readers but whose sputum were negative for AFB (suspect cases). Of these, 38% were tuberculin negative also. Of those suspect cases who were tuberculin positive, 9% become sputum positive after 1½ years, while only 2% of the tuberculin negative suspect cases became sputum positive.

It is concluded that there is a lot of variation in fate among the different categories of cases of pulmonary tuberculosis. Further, attention has been drawn to the possibility of self healing in about 30% of the bacillary cases after 1½ years.

KEY WORDS: FATE, CASE, SUSPECT CASE, NATURAL CURE, PREVALENCE.

012
PREVALENCE, FATE, SOURCE AND INFECTIVITY OF RESISTANT IN MYCOBACTERIUM TUBERCULOSIS
Raj Narain, P Chandrasekhar, Pyare Lal and RA Satyanarayanachar: Proceed Natl TB & Chest Dis Workers’ Conf, Hyderabad, 1967, 37-51.

The material on resistant strains of mycobacterium tuberculosis is derived from the longitudinal survey conducted from 1961-68 in a random sample of 133 villages of 3 taluks of Bangalore district. About 54,000 persons aged five years or more were surveyed 3 times at an interval of 18 months, two samples of sputum were collected from persons whose chest X-rays were judged to have abnormal shadows. The sputum specimens were examined by direct smear and culture and sensitivity tests were performed.

An attempt is made to study prevalence, fate, source and infectivity of resistant mycobacterium tuberculosis in three rounds. PREVALENCE: In the 3 rounds, 199, 194 and 176 cases respectively yielded positive cultures; Of them, 30, 36 and 53 cases were having resistant strains. At round III, the number of culture positive cases has not fallen significantly, but the number of strains resistant to INH alone has sharply increased (13, 18 & 35). Both findings are likely to be due to the treatment with INH alone offered at round II and also due to the fact that treatment was taken very irregularly. FATE: Over period of 3 years, of the cases with INH resistant strains, more than 1/3rd were dead, 1/4th continued to remain positive and resistant, and 1/4th became culture negative. Whereas, of the cases with strains sensitive to INH, less than 1/3rd were dead, 1/3rd became negative and the remaining were positive, 1/2 with sensitive strains and 1/2 with resistant strains. SOURCE OF CASES: The prevalence of cases with resistant strains at any one round is not due to the persistence of such cases from previous rounds but by development of new cases with such strains at each round. INFECTIVITY: The incidence of infection among contacts with sensitive strain was significantly more than among the contacts of cases with resistant strain. It is inferred that the infectivity of sensitive strains is more than that of the resistant strains.

KEY WORDS: M.TUBERCULOSIS, SENSITIVE STRAINS, RESISTANT STRAINS, CASE, FATE, PREVALENCE, INFECTIVITY.

016
SOME EPIDEMIOLOGICAL ASPECTS OF TUBERCULOUS DISEASE AND INFECTION IN PAEDIATRIC AGE GROUP IN A RURAL COMMUNITY
GD Gothi, SS Nair & Pyare Lal: Indian Paediatrics 1971, 8, 186-94.

The prevalence and incidence rates of tuberculous infection and disease in the community are known in the age group 10 years and above from several surveys carried out so far. The present paper provides various parameters of tuberculosis in particular in the pediatric age group. A random sample of 119 villages in 3 taluks of Bangalore district were surveyed 4 times from May 1961 to July 1968 at intervals of 18 months, 3 years and 5 years of the initial survey. Tuberculin test was done for the entire available population with 1 TU PPD RT 23 with Tween 80, and 70mm X-ray for all available persons aged 5 years and above. Two samples of sputum were obtained from the X-ray abnormals, and examined by smear and culture.

It was found that prevalence of infection increased with age from 2.1% at 0-4 year age group to 16.5% at 10-14 year age group, compared to 47% at 15 years and above age group. Prevalence of disease in 5-14 year age group was considerably lower than in age group 15 years or more. Tuberculosis morbidity increased with the size of tuberculin reaction and it was high among children with reaction 20mm or more. Incidence of infection increased with age from 0.9% per year in age group 0-4 years to 2.8% per year among that of 15 years and above. Incidence of disease also showed the same phenomenon-, rising from 0.5% in age group 5-9 to 4% per year in the age group 15 years and above. There were 10 sputum positive cases in 5-14 years of age in first survey, of them, 8 became negative and one died. While from among 152 cases in 15 years and above age group, 48 became negative, 72 died and 32 remained positive. The fate of cases of pulmonary tuberculosis in 5-14 years age was not as serious as in 15 years and above age group. The survey had no means of examining miliary and meningeal tuberculosis.

Children as well as adults with larger reaction of 20mm or more to tuberculin test had higher mortality. This could be considered due to tuberculous infection after taking into account death due to non- tuberculous reasons in both the infected and uninfected groups. Use of chemoprophylaxis might be considered for those who give history of contact with open cases and have tuberculin reaction size 20mm or more.

KEYWORDS: CHILDREN, RURAL COMMUNITY, PREVALANCE, INCIDENCE, INFECTION, DISEASE, TUBERCULIN, INDURATION SIZE, MORTALITY, CHEMOPROPHYLAXIS.

013
PROBLEMS IN DEFINING A “CASE” OF PULMONARY TUBERCULOSIS IN PREVALENCE SURVEYS
Raj Narain, SS Nair, K Naganna, P Chandrasekhar, G Ramanatha Rao & Pyare Lal: Bull WHO 1968, 39, 701-29.

Generally there is no acceptable definition of the term “case of pulmonary tuberculosis”, although such a definition is of fundamental importance both in clinical medicine where results of various chemotherapeutic regimens are compared, as well as for the comparison of different epidemiological data. The main purpose of this paper is to focus attention on the difficulties of defining a case on the basis of bacteriological examination, X-ray examination and tuberculin test. Data from two successive prevalence surveys in a random sample of 134 villages in Bangalore district with a population 70,000 have been utilized to illustrate some of the difficulties in defining a “case” of pulmonary tuberculosis for reporting the prevalence or incidence of the diseases. The entire population was tuberculin tested with 1 TU RT 23 with Tween 80 at both rounds and those 5 years of age and older were examined by 70mm photofluorogram. The sputum specimens (spot and overnight) were collected from those with any abnormality on X-ray as recorded by either of the two independent readers. Both the specimens were examined by fluorescent microscopy and Ziehl-Neelsen technique and by culture.

Analysis of data has shown that the term “a case of pulmonary tuberculosis” does not represent a single uniform entity, but embraces cases of several types, differing considerably in their tuberculin sensitivity, results of X-ray and sputum examination, in the reliability of their diagnosis and mortality experience. The status of cases found at initial and subsequent surveys showed changes with time, and such changes show considerable differences for the various types of cases. It was felt that a single straight-forward definition of a case was not possible to suit all situations. One has to use more than one definition. Although theoretically, finding a single bacillus in sputum should be adequate proof of pulmonary tuberculosis, it was shown that finding of a few bacilli (3 or less) was very often due to artifacts and should not be the basis for a diagnosis. It has also been found that positive radiological findings, in the absence of bacteriological confirmation, indicate only a high risk of the disease and not necessarily pulmonary tuberculosis. Direct microscopy appears to be a consistent index of disease but in community surveys has the limitation of missing a substantial proportion of cases and of adding some false ones.

In view of the difficulty of providing a single definition of a case of tuberculosis, four indices have been suggested. (1) Cases definitely positive by direct smear; (2) Cases definitely positive by culture; (3) All cases positive by culture (including less than twenty colonies); (4) Sputum positive cases which are radiologically active. Each of these could be used for different situations. However, it was concluded that, there seems to be no option but to use more than one definition for assessing the prevalence and incidence of disease.

KEY WORDS: CASE-DEFINITION, SURVEY, PREVALENCE, DISEASE.

017
DISTRIBUTION OF TUBERCULOUS INFECTION AND DISEASE IN CLUSTERS OF RURAL HOUSEHOLDS
SS Nair, G Ramanatha Rao & P Chandrasekhar: Indian J TB 1971, 18, 3-9.

Data from 62 randomly selected villages in a district of south India, which formed part of a prevalence survey carried out by the National Tuberculosis Institute, Bangalore, during 1960-61, has been made use of. The survey covered 29,813 persons in 5,266 households. There were 70 cases with bacilli demonstrable either in smear or culture and 300 suspect cases. Using the village map (prepared by survey staff), ‘case clusters’ were formed first, with each case household as nucleus and adjacent households within a maximum distance of about 20 meters on either side of the case households. Households closest to the nucleus household on either side have been called as 1st neighbourhood and those coming next in proximity on either side as a 2nd neighbourhood and so on. The case household and its four neighbourhood together was called a cluster. If another case household was found within 4th neighbourhood of the first case the cluster was extended by including the 4th neighbourhood of the new case also. Such clusters were called composite case clusters and clusters with only one case household as simple case clusters. Similarly, suspect case clusters were formed and differentiated as simple suspect clusters or composite suspect clusters. Further, to serve as a control group, non-case clusters were constituted from a systematic sample of 10% households that were not included in case or suspect case clusters.

Out of 60 case clusters formed, only 7 have multiple cases showing that there was no evidence of high concentration of disease in case clusters. While the percentage of child contacts (0-14 years) infected was considerably higher in case clusters (25.8%), there was not much difference between suspect case clusters (14.9%) and non-case clusters (9.8%). Similarly, there was not much difference between simple and composite clusters. Infection among child contacts was higher in case households as compared to their neighbourhoods. To get some idea of the zone of influence of a case or suspect case, prevalence of infection was studied for 10 neighbourhoods, in simple clusters to avoid the influence of multiple cases. It appeared that the zone of influence of a case may extend at least upto the 10th neighbourhood. It was also noted that there was very little difference between zones of influence of suspect cases and non-cases. Case clusters in which the nucleus case had shown activity of lung lesion (evident on X-ray reading) or had cough showed significantly higher infection among child contacts. Clusters around cases positive on both smear and culture did not show higher infection than those around cases positive on culture only. (This may be due to sputum examination of single specimen only).

Out of the total infected persons in the community, only 2% were in case households and 7% in suspect case households, over 90% being in non-case households. The zone of influence of a case extending at least upto the 10th neighbourhood and the overlapping of such zones of influence of cases, present and past, seems to be the most probable explanation for the wide scatter of infection in the community. Prevalence of infection among child contacts was definitely higher in case clusters. But, the significance of this could be understood only from a study of the incidence of disease during subsequent years in different types of clusters. It is significant that only 10% of the total infected persons in the community were found in case clusters. The case yield in general population, cluster contacts, household contacts and symptomatics attending general health institutions have been also compared. The case yield in the last group (10%) is much higher than the case yield from both types of contacts (0.7% and 0.6%) which where only slightly higher than the case yield from the general population (0.4%).

KEYWORDS: RURAL, HOUSEHOLDS, CLUSTERS, CASE, SUSPECT CASE, CONTACT, PREVALENCE, INFECTION, DISEASE, SURVEY.

023
TUBERCULOSIS IN A RURAL POPULATION OF SOUTH INDIA: A FIVE YEAR EPIDEMIOLOGICAL STUDY
National Tuberculosis Institute, Bangalore: Bull WHO 1974, 51, 473-88.

A rural population of 65,000 belonging to 119 randomly selected villages of Bangalore district was repeatedly examined four times during 1961 to 1968, by tuberculin test, X-ray and sputum examinations, to study the epidemiology of tuberculosis without any active anti-tuberculosis measures. The interval between the first and the fourth examination was 5 years. The coverage of various examinations at different surveys were very high.

The main findings of the study are: Prevalence rate of tuberculous infection in the population was about 30% (among females 25% and males 35%). The overall prevalence rates of infection were fairly constant at all the four surveys, but a steady decrease in the prevalence of infection was observed in the age group 0-24 years. Annual incidence rate of infection on the average was about 1%. During the study period, the incidence of infection showed a decline from 1.63% to 0.8% for all ages combined. Prevalence rate of disease ranged from 337 to 406 per 1,00,000 population during the study period, the highest being at the time of first survey and lowest at the time of third survey. For the younger age group of 5-34 years, the rates showed continuous decrease during the study period. Annual incidence rate of disease ranged from 79 to 132 per 1,00,000 population, highest being between first and second surveys and lowest between second and third surveys. The incidence rate in younger age groups below 35 years showed a decline during the study period. Those with tuberculin test induration of 20mm or more had highest annual incidence rate of disease. The annual incidence rate of bacteriologically confirmed disease in the three radiological groups of population was (i) 185 per 1,00,000 with normal X-rays, (ii) 958 per 1,00,000 with abnormal shadows judged as inactive tuberculous are non-tuberculous and (iii) 4,530 per 1,00,000 with abnormal shadows judged as active or probably active tuberculous but bacteriologically not confirmed. The third group constituted 1% of the total population and contributed 34% of the total incidence cases. In each of the above three radiological groups, the incidence of disease was highest among those with tuberculin test induration of 20mm or more to 1 TU RT 23 with Tween 80. Those with 20mm or more tuberculin test induration in the third radiological group constituted 0.45% of the total population but contributed 27% of the total incidence cases. Incidence rate for males was nearly double that of females. More than half of the new male cases were 35 years of age, whereas more than half the females were below the age of 35 years. Out of 126 cases followed up at three subsequent surveys over a period of 5 years, 49.2% died, 32.5% got cured and 18.3% continued to remain sputum positive. Both death and cure rates were highest during the first one and a half year period.

About 30% of newly detected cases come from population uninfected at an earlier survey. Both infection and disease showed a decline in the younger age group. There was no evidence of an increase in drug resistance among newly diagnosed cases. Incidence of cases showed a higher natural cure. These findings indicate that tuberculosis cases are not a uniform entity. There can be different gradations from the point of view of diagnosis and ability to benefit from treatment. The differences between male and female patients with regard to death and cure rates support this view

.KEY WORDS: TREND, RURAL POPULATION, PREVALENCE, INCIDENCE, INFECTION, DISEASE, LONGITUDINAL SURVEY.

024
ESTIMATION OF NUMBER OF REPEAT EXAMINATIONS REQUIRED TO DETECT ALL TB CASES IN THE COMMUNITY
R Rajalakshmi & SS Nair: Indian J Public Health 1976, 20, 118-21.

Examination of only one sputum sample cannot detect all the sputum positive cases in the community. To obtain better estimates of the prevalence of bacteriologically confirmed disease in the community, a study was conducted to find out the additional yield of cases through collection and examination of eight sputum specimens and also in order to work out correction factors for estimates based on one or two sputum samples, as collecting multiple sputa is very difficult. The study was carried out in 77 villages in Nelamangala Taluk of Bangalore. In all, 5826 persons were referred for sputum examinations.

Results of all the eight culture examinations were available for 2973 (51% of the eligibles). Of these 64 persons were positive by culture of atleast one specimen. Each of the eight specimens has the chance of detecting a case and any one of them could be considered as first or second specimen etc. To overcome this difficulty 80 permutations were randomly chosen out of the total 40,320 permutations possible. Cases from first specimen and additional cases from subsequent specimens were calculated through four mathematical equations. The first equation namely Y = KXm (28.66 x-1.40) has been considered as providing the best fit to the observed data. On the basis of this equation it appears that additional positives could be obtained upto the 1Oth specimen. Out of 64 culture positive cases, only 72% of positives could be detected by first two samples. To get about 95% of the cases, it is necessary to examine at least six specimens from each individual. Multiple samples are rewarding for detecting even high grade cultures.

KEY WORDS: MULTIPLE SPUTUM SPECIMEN, SPUTUM EXAMINATION, CASE YIELD, PREVALENCE, CASE, SURVEY.

025
PRECISION OF ESTIMATES OF PREVALENCE OF BACTERIOLOGICALLY CONFIRMED PULMONARY TUBERCULOSIS IN GENERAL POPULATION
SS Nair, GD Gothi, N Naganathan, K Padmanabha Rao, GC Banerjee & R Rajalakshmi: Indian J TB 1976, 23, 152-59.

This paper reports on a study conducted in the year 1975 to estimate yield of tuberculosis cases from multiple sputum specimens, and work out correction factors to be applied to estimates based on small number of specimens. Eight sputum specimens were collected within a fortnight from each person with an abnormal chest X-ray during an epidemiological survey in 77 villages in a district of south India. Each specimen was examined by Ziehl-Neelsen technique of microscopy and culture. In all, 3,199 persons were referred for sputum examination and results of all the eight specimens were available for 1,652. Of the latter, 64 were culture positive.

The first specimen detected 58% of the culture positives and the additional positives by later specimens generally decreased. The contribution from the first specimen was 71% for cultures showing good growth and 19% for cultures with scanty growth. Similarly for positives on both culture and microscopy, first specimen detected 87% whereas the corresponding proportion was 32% for those positive only on culture. The type of specimen (viz., spot or overnight) and age or sex of the case did not influence the yield from multiple examinations. The precision of an estimate of prevalence will depend on the number of specimens on which it is based and the coverage obtained in the collection and examination of specimens. Correction factors to be applied to such estimates based on one or two specimens, for various levels of coverage have been presented. For example, an estimate of prevalence based on one sputum specimen with 90% coverage will have to be nearly doubled to get a more precise estimate. Using these correction factors, revised estimates of prevalence have been presented for a number of prevalence surveys conducted in India. It has been estimated that the total number of infectious cases in India at present may be at least 3 million, as against 2 million according to earlier estimates.

KEY WORDS: PREVALENCE, CASE, RURAL POPULATION, MULTIPLE SPUTUM SPECIMEN, ESTIMATES, SPUTUM EXAMINATION.

029
PREVALENCE OF NON-SPECIFIC SENSITIVITY TO TUBERCULIN IN A SOUTH INDIAN RURAL POPULATION
AK Chakraborty, KT Ganapathy, SS Nair & Kul Bhushan: Indian J Med Res 1976, 64, 639-51.

The data from a tuberculosis prevalence survey carried out in three taluks of Bangalore district in south India during 1961-68 were analysed to study (i) the prevalence of non-specific sensitivity in the community i.e., prevalence of infection with mycobacteria other than M.tuberculosis, as found by testing the population with tuberculin RT 23 of a lower strength (1 TU) and higher strength (20 TU), both with Tween 80 and (ii) additional boosting if any, resulting from testing with higher dose of tuberculin, immediately following a test with 1 TU RT 23.

The level of demarcation between infected and uninfected with 1 TU was 0-9 mm induration size and this negative group tested with 20 TU dose induration of 8 mm or more was considered positive. Prevalence of infection with M.tuberculosis in the community were 2.1% in 0-4 years, 7.9% in 5-9 years, 16.5% in 10-14 years, 33.2% in 15-24 years and overall 14.5% in 0-24 years of age group. Infection rate with other mycobacteria were 12.9%, 44.9%, 66.2%, 62.4% and 45.7% respectively in the above stated different age groups.

Testing the population with 20 TU RT 23 following a 1 TU test was found not to boost the tuberculin reactions over that observed on a single test with 1 TU only.

KEY WORDS: NTM, PREVALENCE, INFECTION, BOOSTING, TUBERCULIN REACTION, RURAL POPULATION.

030
ESTIMATION OF PREVALENCE OF BACILLARY TUBERCULOSIS ON THE BASIS OF CHEST X-RAY AND/OR SYMPTOMATIC SCREENING
GD Gothi, Radha Narayan, SS Nair, AK Chakraborty & N Srikantaramu: Indian J Med Res 1976, 64, 1150-59.

The study was undertaken among 22,957 persons belonging to 55 randomly selected villages of Nelamangala taluk of Bangalore district in 1975, to find out precise estimates of prevalence of bacillary disease. Symptom screening was done by well experienced social investigators, according to a brief interview schedule. Sputum was collected from all above the age of 5 years reporting chest symptoms for seven or more number of days during the previous two months. Within two weeks after symptom questioning, all were tuberculin tested and all 5 years and above were X-rayed. Additional sputum collection was done for those asymptomatics who had abnormal shadows in their chest X-rays.

The overall prevalence rate of culture confirmed bacillary cases by symptom and/or X-ray screening was 0.32 percent. Same prevalence was seen with X-ray alone also. But the overall prevalence rate based on symptom screening alone was 0.21 percent which is significantly lower than that of symptom and/or X-ray screening, or X-ray screening alone. The prevalence rates by age and sex based on symptom screening were about two-thirds that of rate based on X-ray and/or symptom screening. Hence to obtain prevalence rate according to X-ray and/or symptom screening, a correction factor of 1.52 should be applied to the prevalence rates obtained by symptom screening alone. This correction factor is fairly good for most of the age groups. It was also estimated that the cost of surveying the population by symptom screening alone is about half that of surveying the population by X-ray screening.

KEY WORDS: PREVALENCE, CASE, SYMPTOM SCREENING, X-RAY EXAMINATION, RURAL COMMUNITY.

031
TUBERCULOSIS IN CHILDREN IN A SLUM COMMUNITY
GD Gothi, Benjamin Isaac, AK Chakraborty, R Rajalakshmi & Sukant Singh: Indian J TB 1977, 24, 68-74.

A study was conducted in a slum area of Bangalore, to get information on the prevalence of all forms of tuberculosis in 0-4 year age group, respiratory tuberculosis in 5-14 year age group and the proportion of respiratory tuberculosis among total respiratory diseases in 0-14 year age group. Entire population in a slum area was investigated. Children aged 0-9 years were given tuberculin test and their nutritional status assessed. All persons were X-rayed. Sputum specimens were collected from those having radiological abnormality in chest, chest symptoms of one week or more in 0-4 years, in addition from those with any kind of sickness, malnutrition and tuberculin reactors.

In 0-9 year age group, 5.5% were tuberculin positive (without BCG lesions), in 0-4 years, 1.8% and 5-9 years, 11.3%. Among the X-rayed children, 47.4% had some kind of sickness, the proportion being significantly high in 0-4 year age group. The respiratory sickness is the commonest among children of all ages followed by malnutrition (21%). Among children with chest symptoms, upper respiratory infections were 33%. Chest X-ray abnormalities were present in 4.5% of children and of these 82.5% had non-specific pneumonitis. Of 71 persons with respiratory disease, about 7% were tuberculous. Out of 1408 children, only 5 had active primary tuberculosis, giving a prevalence of 0.35%. None in 0-4 year age had sputum positive disease or extra pulmonary tuberculosis.

It has been highlighted that non-tuberculous chest diseases are common in pediatric age group and many of these may be wrongly classified as active tuberculous in practice. It is concluded that tuberculosis in the pediatric age group in this community is not a serious public health problem.

KEY WORDS: CHILDREN, SLUM COMMUNITY, PREVALENCE, INFECTION, PEDIATRIC TUBERCULOSIS.

033
USE OF 20 TU RT 23 AND 5 TU BATTEY ANTIGEN FOR ESTIMATION OF PREVALENCE OF NON-SPECIFIC TUBERCULIN SENSITIVITY
GD Gothi, AK Chakraborty, MJ Jayalakshmi & KT Ganapathy: Indian J Med Res 1977, 66, 389-97.

Estimates of prevalence of non-specific tuberculin sensitivity in south Indian population are based on studies using large doses of tuberculin prepared from Mycobacterium tuberculosis. In the present study, comparison of tuberculin test done on 2168 children aged 0-9 years with 20 TU RT 23 and 5 TU Battey antigen, belonging to rural areas, have been done. The distribution of induration to 20 TU RT 23 test has been compared to that of 5 TU Battey test, to see whether estimates of prevalence of non- specific tuberculin sensitivity based on the former could be compared with those based on tests with antigen derived from other mycobacteria.

It was seen that distributions of reactions, mean size of indurations as well as percentages of positive reactors to either test were not significantly different in the two randomly selected groups i.e., one tested with Battey antigen and the other with 20 TU RT 23. The prevalence of non-specific sensitivity in 0-4 years age group based on Battey test was 18.4 per cent and that with 20 TU test, 16.6 per cent. In the age group 5-9 years corresponding rates were 54.2 and 60.1 per cent. From these observations, it is suggested that if other antigens are not available, 20 TU RT 23 could be used for estimation of non-specific sensitivity.

KEY WORDS: BATTEY ANTIGEN, PREVALENCE, NON SPECIFIC INFECTION.

037
PREVALENCE AND INCIDENCE OF SPUTUM NEGATIVE ACTIVE PULMONARY TUBERCULOSIS AND FATE OF PULMONARY RADIOLOGICAL ABNORMALITIES FOUND IN A RURAL POPULATION
GD Gothi, AK Chakraborty, VV Krishnamurthy & GC Banerjee: Indian J TB 1978, 25, 122-31.

A study was carried out mainly to find out the prevalence and incidence of sputum negative active pulmonary tuberculosis (suspect cases) among 35,876 persons aged 5 years and above in rural areas of Bangalore district during 1968-72. Two surveys (I & II) at an interval of 3 months, succeeded by a follow up examination of the X-ray abnormals of the earlier surveys, were conducted in the same villages. Examinations at each survey consisted of tuberculin test, X-ray and sputum examinations. X-rays were interpreted individually at the time of each survey by single picture interpretation method and subsequently by Joint Parallel Reading (JPR) method to arrive to a diagnosis. In the JPR method X-ray readings and their comparison was done by a panel of three X-ray readers with full knowledge of age, sex, result of sputum examination and tuberculin test of each person with chest abnormality at any of the three surveys.

On a single picture interpretation the overall prevalence rate of suspect disease was found to be 5.4 per thousand at I survey and 4.59 per thousand at II survey. There was no significant difference in the overall age and sex specific prevalence rates of suspect disease between I & II surveys. Incidence of suspect disease at the end of 3 months was 2.24 per thousand. By JPR method the prevalence rates of suspect disease was 3.2 per thousand at I survey and 3.6 per thousand at II survey. The prevalence rates by single picture method were overestimated to the extent of 38% at I survey and 19% at II survey when compared with those found by JPR method. At I survey prevalence rates on JPR method was significantly lower than by single picture method. This was not so at II survey. Similarly, incidence rate of 0.2 per thousand of suspect disease on JPR was about 1/10th of that found by single picture method.

The incidence of bacteriologically positive cases in 6 months from among suspect cases on JPR was found to be 28%. Majority (76%) of non-tuberculous or inactive tuberculous shadows continued to remain as such after 6 months and about a quarter (23%) became normal. Incidence of bacteriologically positive cases from this group was minimal. Of 19,640 persons with normal X-rays 134 (0.7%) developed new shadows in 3 months; 103 (0.5%) cleared after 2-12 weeks (fleeting shadows). Mis-interpretation of the latter as active tuberculous may falsely boost the estimates of suspect disease to the extent of about 5%.

KEY WORDS: SUSPECT CASE, PREVALENCE, INCIDENCE, RURAL POPULATION, FATE.

041
CHEST DISEASES AND TUBERCULOSIS IN A SLUM COMMUNITY AND PROBLEMS IN ESTIMATING THEIR PREVALENCE
AK Chakraborty, GD Gothi, Benjamin Issac, KR Rangaswamy, MS Krishnamurthy & R Rajalakshmi: Indian J Public Health 1979, 23, 88-99.

The entire population of a slum area of Bangalore city, comprising of 3313 persons was registered, questioned for symptoms and offered chest X-ray at a centre located in the slum itself. Those, who had any chest symptom and/or X-ray abnormality, were offered detailed examinations, viz., clinical examinations, repeated examinations of sputum for tubercle bacilli, and further chest X-rays. Of the total 2855 persons X-rayed and/or questioned, 1039 needed detailed examinations and about a fifth of the latter required referral to a consultant panel for diagnosis of chest diseases. Further, about 60% of those referred to consultants needed special investigations. Thus, the study of prevalence of chest diseases in the community needed considerable facilities and were operationally difficult. It is envisaged that similar problems will also be faced if peripheral dispensaries are to make proper diagnosis of chest diseases, due to the need for referral of large number of patients and provision of complicated diagnostic facilities at the referral hospitals. The study seeks to quantify the problem of chest diseases and tuberculosis in the slum community.

The prevalence of sickness in the population at any point of time were 49.5%. Sickness related to the respiratory system was 13.3%. It increased with age and was highest (42.6%) in those aged 55 years and above. Among 2855 persons X-rayed, 145(5.1%) had any radiological abnormality in chest. It is seen that respiratory systems symptoms were commonest in all the age groups. A total of 172 patients were diagnosed to have respiratory system abnormalities with or without X-ray lesions. Of them, 75% had non- tuberculous etiology, 7.6% had active pulmonary tuberculosis and the remaining 17.4% had inactive tuberculosis. Prevalence of sputum positive cases was 0.26% and prevalence of total active pulmonary tuberculosis was 0.44%. The problem of arriving at final diagnosis was dependent on application of complicated special investigation tools to a large community. In view of the low coverage (47.4%) for the special investigations, prevalence of different chest diseases in the community could not be investigated.

It is concluded that in the community under study, the size of the problem of non- tuberculous diseases of the chest and operational problems in their diagnosis were considerable.

KEY WORDS: PREVALENCE, URBAN, SLUM COMMUNITY, CHEST DISEASES, CASE.

043
PREVALENCE OF INFECTION AMONG UNVACCINATED CHILDREN FOR TUBERCULOSIS SURVEILLANCE
AK Chakraborty, KT Ganapathy & GD Gothi: Indian J TB 1980, 72, 7-12.

A survey was carried out among 12,535 children in the age group 0-9 years of 90 villages in Doddballapur sub-division of Bangalore district to study the possible variation in the prevalence of tuberculous infection among the unvaccinated children in a village depending upon the varying prevalence of BCG scars in the same population. In each village, all the children in the age group of 0-9 years were registered and examined for the presence or absence of the BCG scar. Of the 12,535 children, 6269 (50%) who did not have BCG scars were eligible for tuberculin test, while 6045 were actually tested. Each child without BCG scar was tuberculin tested with 1 TU RT 23 with tween 80 and the reaction read between 72 and 96 hours. Two proportions were calculated in each village viz., a) the proportion with BCG scars and b) that of infected children among those without scar and the villages were distributed by these two proportions.

On the basis of distribution of tuberculin reactions, 10 and 12 mm induration was the demarcation between positive and negative reactors. Prevalence of infection among 0-9 years was 4.9%, 2.6% among 0-4 years and 8.9% among 5-9 years. Distribution of villages according to two variables i.e., prevalence of BCG scars and prevalence of infection among unvaccinated children did not show any correlation with the prevalence of infection among the unvaccinated in the same villages.

It is seen from the study that exclusions of various proportions of children with BCG scars did not have any correlation with the prevalence of infection among the unvaccinated in the same villages.

In non-e of the villages any association was seen between these two. In view of this finding, it is felt that the simple method of periodic tuberculin testing of the population in younger age groups could be developed into a method of tuberculosis surveillance even in areas where direct mass BCG vaccination is given. This would appear to be the cheapest, practicable and technically appropriate method of studying the overall tuberculosis situation.

KEY WORDS: PREVALENCE, INFECTION, BCG SCAR, SURVEILLANCE.

048
PREVALENCE, INCIDENCE AND FATE OF SUSPECT CASES OF TUBERCULOSIS IN A RURAL POPULATION OF SOUTH INDIA
VV Krishna Murthy: NTI Newsletter 1982, 19, 75-80.

The data from a longitudinal survey conducted in Bangalore district from 1961-1968 by National Tuberculosis Institute was analysed to find out the prevalence, incidence and fate of suspect cases. In brief, the survey was conducted in 119 randomly selected villages in three taluks of Bangalore district and repeated within the next five years. At each survey, eligible population was subjected to tuberculin, X-ray & sputum smear and culture examinations.

The overall prevalence rate of suspect cases among persons aged five years and more was 1.06% at I survey, 0.68%, 0.49% and 0.43% at II, III and IV survey respectively. In males, the prevalence rate was 1.19% at I survey & 0.62% at IV survey corresponding figures for females were 0.94% and 0.24% respectively. A decline of prevalence of suspect cases from 1.06% at I survey to 0.43% at IV survey was observed. The overall incidence of suspect cases was 0.16% between I & II surveys, 0.10% between II & III, and 0.06% between III & IV surveys. The overall as well as age specific annual incidence rates between III & IV surveys were significantly less than that between I & II surveys. At all the three intervals the incidence increased with the age. Incidence of suspect cases in males was more than that in females. Change in disease status over a period of time is termed as "fate". The disease status was classified as (i) cure (ii) continued to be suspect case (iii) converted into bacillary cases and (iv) dead. The percentage of cure (51.9%, 53.2% and 50.3%) and conversion into bacillary cases(7.2%,5.8% and 5.4%) were almost the same at all the three intervals. But the percentage of those who remained suspect cases reduced from 33.5% at the end of 18 months to 17.5% at the end of 60 months. On the other hand, the death rate increased from 7.4% at the end of 18 months to 26.8% at the end of 60 months. The decreasing trend of continuing to be suspect cases at the rate of 10% between two observations, appears to be corresponding to the increasing trend in the death rate as seen from the observations made at the three intervals.

KEY WORDS: PREVALENCE, INCIDENCE, FATE, SUSPECT CASE, RURAL COMMUNITY, LONGITUDINAL SURVEY.

049
TUBERCULOSIS IN A RURAL POPULATION OF SOUTH INDIA: REPORT ON FIVE SURVEYS
AK Chakraborty, Hardan Singh, K Srikantan, KR Rangaswamy, MS Krishnamurthy & JA Steaphen: Indian J TB 1982, 29, 153-67.

The trend of tuberculosis in a sample of 22 villages of Bangalore district observed over a period of about 16 years (1961-77) is reported. Distribution of tuberculin indurations did not show a clear cut demarcation between infected and non-infected. The method adopted to demarcate the cut off point has been described herewith: Distribution of tuberculin induration size of 0-14 years was attempted and extrapolated to higher age groups. Even in these younger age groups the antimodes were not clearly defined, so the antimode was arrived by fitting two normal curves as two likely modes.

The choice of demarcation level, therefore, is somewhat arbitrarily made on the basis of the distributions and these varied from survey to survey; between 10 mm at survey I and 16 mm at survey V. The actual and standardized infection rates showed more or less declining trend in 0-4 years, 5-9 years and 10-14 years age groups. The prevalence of cases was not significantly different from survey to survey (varying from 3.96 to 4.92 per thousand from first to fifth survey). However, there was a shift in the mean age of cases, and better survival rate of cases diagnosed at later surveys.

KEY WORDS: TREND, CASE, INFECTION, PREVALENCE, TUBERCULIN READING METHOD, LONGITUDINAL SURVEY.

052
CHANGES IN THE PREVALENCE RATES OF INFECTION IN YOUNGER AGE GROUPS IN A RURAL POPULATION OF BANGALORE DISTRICT OVER A PERIOD OF 5 YEARS
AG Kurthkoti & Hardan Singh: NTI Newsletter 1985, 21, 28-40.

The utility of repeated estimates of prevalence rates of infection in children as a tool for surveillance in tuberculosis is now well recognized. Two prevalence surveys at an interval of 5 years were conducted by National Tuberculosis Institute, Bangalore, with the main objective of studying changes in prevalence rate of infection among children in the age group of 0-9 years. A total population of 42,343 residing in 90 randomly selected villages of Doddaballapur taluk, Bangalore, were registered; of them, 12,535 were children in the age group of 0-9 years. Children were further classified into two sub groups 0-4 and 5-9 years, with or without BCG scars. The unvaccinated children in these two age groups formed the study population.

The population in the study area during the 2nd repeat survey was similar to that of first survey with regard to age, sex distribution, except that a growth rate of 1.1% per year was registered. The BCG scar rate, among children in the age group 0-4, 5-9 years, was 8% & 39% respectively at survey I. All the unvaccinated children below 10 years were given tuberculin test with 1 TU PPD RT 23 and reactions were read 72 to 96 hours after tuberculin testing. In the first survey, level of demarcation to classify the infected children was 10 mm and above, while in II survey it was 12 mm and above. It was observed that the prevalence rate of infection from I survey to II survey was not altered (2.58% & 2.46%) in the 0-4 years of age, while there was an increase in the rate from 8.93% to 12.3% in 5-9 years of age in the II survey. The increase in the infection rate could be attributed to the rising trend of infection, over reading by tuberculin-readers', skills of both tuberculin tester and reader, boosting of tuberculin reaction or scarless BCG vaccination. In conclusion, the study of changes in the prevalence rate of infection in the younger age group is simple, cheap, less time consuming. The data can be used for calculating annual risk of infection as well trend of transmission of infection.

KEY WORDS: TREND, RISK OF INFECTION, PREVALENCE, SURVEILLANCE, RURAL COMMUNITY.

063
PREVALENCE OF PULMONARY TUBERCULOSIS IN A PERI-URBAN COMMUNITY OF BANGALORE UNDER VARIOUS METHODS OF POPULATION SCREENING
AK Chakraborty, R Channabasavaiah, MS Krishna Murthy, AN Shashidhara, VV Krishna Murthy & K Chaudhuri: Indian J TB 1994, 41, 17-27.

Screening of the population by Mass Miniature Radiography (MMR) followed by sputum examination by culture of the X-ray abnormals is the customary method for arriving at the prevalence rate of cases in the community. It is not possible to use this methodology by states to carry out prevalence surveys in these areas, even if they desire to evaluate the effect of anti tuberculosis measures implemented by them. Therefore, simpler means of screening population through chest symptom for sputum examination has been studied by National Tuberculosis Institute (NTI). The objectives of the present investigation were to find out the prevalence of bacillary cases by screening the population through identification of chest symptomatics by Social Investigators (Sls) or General Health Workers (GHWs) compared to that by MMR. In a peri urban area 10 kms away and around Bangalore city all the villages were listed and of the 60 villages were selected on the basis of a sample random sample. Of them, 30 were covered by Sls of NTI and the other 30 by GHWs of the state government. The methodology adopted was that (1) After census taking and registration of the entire population aged 15 years and above, Sls questioned the persons house to house for presence of cardinal chest symptoms of any duration. All chest symptomatics were subjected to MMR and sputum examination. (2) Similar methodology was adopted by GHWs in the other 30 villages allotted to them. (3) Without knowing the symptom status of all the registered persons, aged 15 years and more belonging to all the 60 villages, were subjected to MMR and from among those having X-ray abnormalities, to sputum examination.

It was found that GHWs had identified the same proportion of the persons either having general symptoms or having chest symptoms from the general population, as Sls. Prevalence rates of culture positive as well as smear positive cases were similar by any of the three methods i.e., 0.18%, 0.23% & 0.25% respectively. Prevalence rates of smear positive cases obtained through symptom questioning, either by Sls or GHWs, were more or less similar to the estimates obtained by the more comprehensive screening method of MMR and/or symptom questioning. The culture positive prevalence rate following MMR screening was 0.25%, which was lower than the rates observed in other surveys. The paper discusses the possible hypothesis that could explain the observation. It also presents correction factors to compute rates comparable to the best estimate i.e., that obtained through comprehensive screening by MMR and/or symptom questioning, followed by sputum culture.

KEY WORDS: SCREENING TOOLS, CHEST SYMPTOMATICS, MMR, PREVALENCE, CASE, PERI URBAN COMMUNITY.
 

 
  SOCIOLOGY  
 
 
070
A SOCIOLOGICAL STUDY OF AWARENESS OF SYMPTOMS AND ACTION TAKING OF PERSONS WITH PULMONARY TUBERCULOSIS (A RESURVEY)
Radha Narayan, S Prabhakar, Susy Thomas, S Pramila Kumari, T Suresh & N Srikantaramu: Indian J TB 1979, 26, 136-46.

A study on awareness of symptoms of pulmonary tuberculosis and action taking was repeated in the 62 villages and 4 town blocks of Tumkur district of Karnataka after an interval of 12 years. In the earlier study, 2106 persons formed the study population. In the present study, 1752 were intaken to obtain a comparison of these 1752 intaken persons who were eligible for interview, 875 were X-ray positive and 877 X-ray normal (matched control).

The study showed that 95% of patients having radiologically active tuberculosis by both X-ray readers, 70% by one reader, 49.5% inactive by both readers, were aware of symptoms. According to the bacteriological status 79.5% had symptoms among those who were sputum positive by both microscopy and culture, 62.2% among those positive by culture alone and 73.7% among patients sputum positive by any method. Regarding action taking it was observed that 49.5% of the bacteriologically positive patients took some action compared by 70% of those found to have radiologically active disease by both X-ray readers. Thus action taking was higher among the latter category in both the studies. It may be due to the fact that extent of lesions are less advanced among those bacteriologically positive than among those who were in radiologically positive stage.

The findings of the study are similar to the earlier awareness study carried out in 1963 in the same area (Tumkur). This also indicates that in spite of having advantage of DTP for a decade actual and total benefits have not reached the people.

KEY WORDS: SOCIAL AWARENESS, ACTION TAKING, SYMPTOMS, RURAL POPULATION, URBAN POPULATION, INTERVIEW, CONTROL PROGRAMME.
 
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