Information on cause specific mortality rates due to tuberculosis in India is inadequate. In the study under report, these have been estimated based on the data obtained from a five year epidemiological study of 119 villages of Bangalore district in south India. For this purpose, the estimated number of excess deaths due to causes other than tuberculosis among patients of tuberculosis, have been attributed to the disease.

The annual mortality due to all causes on 5 year observation could be calculated as 893 per 1,00,000 population (9%) aged 5 years and above. Agewise as well as overall mortality rates were not different from survey I & II, II & III & III & IV. The average rate of the periods is calculated to be 84 per 1,00,000 annually. The death rates were the highest in 55 years and above age groups, lower in 5-14 years and showed an increasing trend with age. Compared to the estimates of tuberculous deaths in India available for 1949 (about 250/1,00,000), the present rates were lower.

Contact examination is not recommended as a routine procedure for Case-finding in the District Tuberculosis Programme. The rationale for not including contact examination as a routine Case-finding measure is: (1) prevalence rate of tuberculosis among the contacts is not much higher than in the general population (2) at the time of diagnosis of an index case, a second case may not be found in the same household. Though more prevalence cases cannot be diagnosed by contact examination, is it possible that by keeping the household contacts, as a group, under surveillance, future incidence of cases in the community can be substantially prevented? A model situation has been created by using hypothesis derived from various studies conducted in India, designed to answer the question. Variables used in the model are: 40% of the general population are infected at any point of time, there is only one prevalence case of TB at any given point of time in an average household of five, 40% of the non-infected population in a contact household are infected per year, incidence of disease among newly infected group is seven, times of the incidence among previously infected, incidence of disease in general population is 0.13% and from among previously infected persons 0.3% per year develop sputum disease.

At an incidence rate of 0.13% per year among general population aged >5 years, it is expected that 111 cases would arise in a year in the population of 1,00,000 under study. Thus, of the 111 cases occurring in the community, 101 arise from those who are not contacts.

The proportional contribution of new cases from the contact group to the total incidence cases in the entire community is so small, that even if all the contacts are kept under surveillance, BCG vaccinated or placed on chemoprophylaxis, still over 90% of incidence cases cannot be prevented from occurring. This is apart from the fact that keeping them under surveillance will be highly costly and is an operational problem of considerable magnitude.

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.

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.

A study on acceptability of BCG vaccination, through specialised technicians in a population of 8350 residing in 8 villages of Channapatna taluk of Bangalore district, was carried out by National Tuberculosis Institute. Of the 1106 households satisfactorily interviewed, 956 (86.4%) had at least one child eligible for vaccination. For the purpose of analysis they were classified into three groups. Group I consisted of 312 (32.6%) households in which all children were vaccinated, Group II 270 (28.2%) where non-e of the children were vaccinated and Group III 374 (39.2%) households where only some of their children were vaccinated. Overall vaccination coverage was 52.7% with a range of 33.9% to 79.3%.

The reasons for refusing vaccination were studied. The caste, occupation, education etc., of the household did not have any influence on the refusals. When analysed according to the knowledge and opinion about vaccination it was observed that 55.9% of the children were not vaccinated because of the lack of knowledge in the group where no child was vaccinated. Even when 42% had favourable opinion about vaccination, 52% of the households did not vaccinate any of their children. The refusals were mainly due to (i) absence from the village on the day of vaccination, (ii) fear of prick. Among households where there was unfavourable opinion, all had refused due to fear. The reasons for accepting BCG vaccination were (i) the vaccination was done in the school and hence there was no option for the parents to accept or refuse, (ii) parents felt that the vaccination was good for children, (iii) parents knew that it would prevent TB.

The effect of initial motivation on pulmonary tuberculosis patients in terms of regularity of drug collection and pattern of default for three months was studied at Lady Willingdon Tuberculosis Demonstration & Training Centre (LWTDTC), by adopting three different schedules of motivation (i) motivation as per routine procedures of District Tuberculosis Programme (ii) issue of simple brief instructions only and (iii) motivation with reduced contents and with change in sequence of points. The patients without history of previous treatment were randomly allocated to these 3 groups. All the three groups were similar in respect of age and sex composition, sputum status, extent of disease, duration of symptoms, education level and the distance that the patient had to travel for collection of drugs. However, there were more housewives in Group II.

The findings of the investigations were: Of the 139 patients in Group I, 49.6%, of the 126 in Group II, 46.7% and of the 142 in Group III, 47.2%, had made all the three collections. On the whole different schedules of motivation did not significantly affect the behaviour of the patients in making all the three monthly collections. However, patients in Group II with simple instructions were more regular and made less number of defaults. There was also a suggestion that sputum negative patients required more than mere instructions. The best response in such cases was in Group III, wherein motivation was neither very elaborate nor very brief and in which sequence of points was so arranged that stress on important points was laid early enough to remain within the recalling memory of the patients.

A controlled study was conducted at Lady Willingdon Tuberculosis Demonstration and Training Centre (LWTDTC), Bangalore among 250 patients randomly selected urban patients of pulmonary tuberculosis of whom 155 were in the 'motivation' group and 95 were in the 'control' group. In the motivation group, patients were interviewed by National Tuberculosis Institute health visitor and motivated by LWC staff; a month of drugs (TH) were given. Within 3 days of initiation of treatment they were motivated along with their household members during home visit by NTI staff every month for a period of three months. Control group patients were motivated at the clinic as per the programme guidelines.

In the motivation group, 59.9% of patients had made all the three collections during the first three months compared to 27.8% in the 'control' group. During the remaining months also the drug collection was 47% and 35.6% respectively. The drug collection pattern among the patients in the motivation group was found to be better than among the patients in control group who did not have the benefit of home visiting. Sputum conversion was also found accordingly better among the motivation group as compared to control group.