Because of slow nature of decline and the long span of the declining phase spread over a couple of centuries it is difficult to obtain direct evidences of decline by conducting studies over relatively short period of time and comparing the rates so obtained. Therefore, one has to take into account the total current epidemiological situation by considering both indirect and direct evidences to know the trend of disease; A) Indirect Evidence i) tuberculosis morbidity being largely confined to older age groups, prevalence rates being similar in both rural and urban areas and a wide gap between infection and disease rates (38% and 0.4% respectively). ii) Information on tuberculosis mortality although not very reliable, still appears to suggest that the disease, since the turn of the century, has taken a declining course. It has been observed to be 253 for 100,000 persons in 1949 in Madanapalle and 84 per 100,000 in Bangalore during 1961-68. There might he some regional variations but there is definite suggestion of decline in the mortality. iii) Considerable change in clinical presentation from more acute and exuberative to a more chronic disease and a shift in age during last quarter of the century, a marked decrease of the concomitant problems of pulmonary tuberculosis, are all indirect indicators of decline. B) Direct evidences are: i) Information available from various epidemiological surveys in India indicates no change in the prevalence rates of bacillary tuberculosis in the country during the last two decades. ii) The longitudinal survey conducted in south India and the other in Delhi have shown a declining trend of the disease specially in the younger age group. However, to see that the trend is secular or not, these surveys have to be continued for a longer period of time - atleast 15-20 years.

From the above evidences it may be reasonable to infer that there is a gradual but slow natural declining trend of tuberculosis in the country. To hasten the process of natural decline and to give relief to a large number of prevailing cases, anti tuberculosis measures should be further strengthened.

At present, Case-finding activity of tuberculosis through the self reporting chest symptomatics attending Peripheral Health Institutions, is at a low ebb. With the introduction of Multi Purpose Workers (MPW) scheme, a machinery has emerged through which this activity could be augmented. An operational study was therefore undertaken in five Primary Health Centres (PHCs) of Chittoor district, Andhra Pradesh in June 1978.

The study has revealed that if the MPWs collect sputum smears from the symptomatics of the age group of 20 years and above during their routine visits to each household of the specified population allotted to them and despatch the smears to the PHC for examination, there is a possibility of augmenting the existing Case-finding activity by 4 5 times. An intensive training of 2 3 days for this purpose seems adequate. The average work load for a MPW would be preparation of one smear a day initially for a couple of months and thereafter as a routine one smear a week. In an average PHC, the work load for the microscopist would be to examine 10 to 12 slides a day initially, the load will then progressively decline and subsequently as a routine it will not be more than 3 4 slides a day. An additional microscopist would probably be needed at PHC laboratory for examination of sputum smears as well as to assist the existing microscopist who at present is primarily engaged in malaria work. Meticulous supervision and regular flow of supplies and equipment is however a 'must' for the success of the scheme.

The effect of specific anti TB drugs on patients having smear negative radiologically positive pulmonary tuberculosis (suspect cases), was studied in Lady Willingdon Tuberculosis Demonstration & Training Centre (LWTDTC), Bangalore during 1975 & 1976. The main objective was to know the proportion of suspect cases treated under the programme requiring the specific treatment with anti TB drugs. A total of 457 suspect cases were randomly allocated to one of the two regimens; 228 patients were treated with INH + Thioacetazone (TH) and 229 with calcium gluconate (Placebo) regimens, for one year. The placebo group allowed a concurrent comparison of status of suspect cases without any specific treatment. After the intake, sputum examination by direct smear, culture for M.tuberculosis and sensitivity for drugs as well as X-ray examinations were carried out at 0, 2nd, 4th, 6th, 9th and 12th month of treatment.

Among the 228 patients on TH, 103 (45.2%) were real suspect cases, 83 (36.4%) sputum positive and remaining 42 non- tubercular. Similarly, out of the 229 patients on placebo regimen, 110 (48%) were real suspect cases, 61 (26.5%) sputum positive and 58 non- tubercular. The effect of treatment was measured by observing the incidence of bacteriologically positive or radiologically active disease from among the real suspect cases of the two groups. At the end of the treatment period, 12.6% of TH group and 29.7% of placebo group were broken down, the difference being statistically significant. Further, an element of self healing was also observed, as about 40% of patients in placebo group showed either clearance of lesions or continuing regression which could be due to self healing or the lesion being non- tubercular in nature. About 30% of the 457 patients at the start of the study were real cases of tuberculosis who under the programme were missed and 20% broke down with bacteriological positive or progress to radiologically active disease when treatment was not offered. Thus, nearly 50% of the suspect cases diagnosed in the programme required anti TB treatment and for those requiring treatment, perhaps TH is not sufficient, as 12.6% broke down in spite of treatment. It would be appropriate to treat suspect cases both from the clinical and epidemiological point of view after taking due precautions to remove non- tubercular cases by doing repeat sputum examination.

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.

An operational study to understand the influence of training of Peripheral Health Institution (PHI) Medical Officers (MOs) at District Tuberculosis Centre (DTC) in comparison to on the job training in their own PHIs in carrying out case-finding activity, was carried out in districts of Mysore, Mandya, Bellary and Hassan of Karnataka State in 1980 81. These districts are now being referred as I, II, III and IV respectively. From each district, 20 Microscopy Centres (MCs) were selected. All the selected MCs of the above four districts after stratified random allocation were divided into two groups, i.e., A & B. The MOs of Group A of each district were trained for 2 days in Case-finding activity at the respective DTCs by District Tuberculosis Officer and District Health Officer, while the MOs of Group B were given on the job training as per manual. In all, 108 MOs: 52 in Group A and 56 in Group B were under study. The performance of each PHI was monitored in terms of number of new Out patient Attendance, selection of chest symptomatics for sputum examination and number of smear positive cases detected, for a period of 12 months after the training.

At the end of one year it was observed that there was a boosting in case detection in districts I and III, no effect in district II and negative effect in district IV. The efficiency in districts I and III was higher by methodology A. It was enhanced from 7.6% pre-training efficiency to 16.7% after training and in district III, 18% to 65.8%. The enhancement with methodology B was from 5.5% to 8.1% in district I and from 19.1% to 43.2% in district III. The average increase by amalgamating all the four districts was from 8.5% to 17.8% with methodology A and from 9.7% to 12.3% with methodology B. There was a suggestion of better improvement through methodology A, which, however, did not attain statistical significance.

In the districts under study, Case-finding was at a very low ebb. Systematic training by either of the two methodologies, did improve the activity in I and II i.e., in two of the four districts. In districts II and IV other variables might also have been at work e.g., training variables of knowledge, skill and communication abilities of DTOs who were trainers could have influenced the outcome.

The high rate of treatment completion and the regularity of drug intake achieved in clinical trials of Short Course Chemotherapy (SCC), could possibly be attributed to efficient organizational set-up, careful selection of cases and all-out effort to control defaulters. The organizational effort put forth to achieve the regularity is relevant to the applicability of SCC in the existing set-up of District Tuberculosis Centres (DTCs) under National Tuberculosis Programme (NTP). First 300 patients admitted to SCC trial to assess the efficacy of three drug regimens of 3/5 months duration under fully supervised conditions, carried out jointly by National Tuberculosis Research Centre, Madras and National Tuberculosis Institute (NTI), Bangalore, have been analysed for the purpose.

To keep up the regularity, 1/3rd of the patients required home visits-some of them repeatedly. If the actions of the same intensity of defaulter retrieval in the form of home visiting are envisaged to be taken in a DTC with the normal working pattern catering to 500 patients, 250 to 300 home visits will have to be made in a month. This may not be feasible in the existing set-up of NTP. A new strategy of defaulter retrieval actions for programme conditions may have to be devised. Further, selection of drug regimen which has the maximum potential of being given on self-administered basis may reduce the work-load to a considerable extent. Drug toxicity, side effects and the cost of drugs may not be major handicaps. However, the only way to understand various operational problems is to undertake scientific operational studies in actual working conditions of NTP.

Feasibility of introducing limited active case-finding in tuberculosis involving Multi-purpose Health Workers (HWs) to supplement the existing methodology of detecting the cases through chest symptomatics attending Peripheral Health Institutions (PHIs) on their own, was studied earlier with encouraging results. The present study was undertaken to understand the existing working system of HWs and within that the priority areas of input which may lead to better case yield.

The study revealed that the population available at any beat schedule of HWs was about 42% of the eligible population of age 20 years and above. Only 60-75% of the field days were utilized for routine multi-purpose duties. Of the total area, 25% to 40% remained uncovered. The effective tuberculosis work was done only on 5% of the beat schedule days and the work was not uniformly spread throughout the month. Even so, the contribution by HWs was twice the number of cases diagnosed at PHIs under study in one year. Had the HWs covered the entire area of their beat schedule, 80 against 26 cases would have been diagnosed. Moreover, there is possibility of detecting more cases among the elderly patients who normally do not attend their area health centres. However, the success depends upon meticulous supervision and regular flow of supplies.