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.

Survey with MMR remains as one of the most important methods available for measuring the size and extent of tuberculosis, specially in developing countries. Its value in case-finding programmes is well recognised. Nevertheless, mass miniature radiography with a single picture of the chest has a wide margin of error owing to the intra & inter-individual differences in X-ray reading. A study was undertaken to know the errors involved by repeating an X-ray picture after an interval of 3 to 4 months and judging the first picture in the light of a comparative reading of the two pictures. It is postulated that two pictures taken at an interval, may afford better judgement regarding the assessment of a case than a single picture only. A prevalence survey was carried out in Tumkur district in 1960-61, among 62 villages and 4 towns; 20 villages were selected for this study. A total of 8,000 persons were registered, 5,300 of them were X-rayed and re-read by two readers. Photofluorograms were repeated after three and a half months after the first picture. At the time of repeat X-ray, a spot sample of sputum was collected from persons with abnormal shadows.

Briefly the findings of the study were: (1) About 20% of bacillary cases were among those with inactive or non- tubercular shadows on the basis of a single X-ray film. (2) Inter-individual agreement for X-ray active cases was of the order of 50%. (3) Intra-individual agreement for X-ray active cases was 52% for one reader and 69% for the two readers. (4) Mass miniature radiography with a single film, in spite of its inherent limitations, is the best available method both for surveys as well as for case-finding programmes due to its ability to find cases as well as potential cases in a short time. (5) Even the agreement between two sputum samples collected within an interval of 1-3 days was 42% for positive results.

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.

In all, 1,259 students aged 11-19 years from three boys high school of Bangalore, formed the study group. They were tuberculin tested with 1 TU RT 23 containing Tween 80. Boys with a reaction of 13 mm or less to tuberculin test and willing for BCG vaccination were allocated in 3 groups: (i) to be vaccinated with Madras vaccine (211), (ii) to be vaccinated with Danish Vaccine (236), (iii) control with saline injection (231) (placebo). Strength of Madras and Danish vaccines used was same, 0.075 mg per dose. After 3 months of vaccination, second tuberculin test with 1 TU RT 23 with Tween 80 was given to 575 boys included in both the vaccinated groups and in the control group. A follow up at one year after vaccination was done among 328 boys, who were again tuberculin tested.

The analysis of data shows that the mean size of post-vaccination tuberculin test induration among Madras BCG vaccinated group was 11.8 mm and among Danish BCG vaccinated group, it was 11.9 mm, the standard deviation were 3.8 and 4.5 mm respectively. The above differences between the 2 vaccinated groups were not-statistically significant. Similarly, the post-vaccination allergy in the two BCG vaccinated groups at the end of one year was not-significantly different. The mean size of the scar produced by two vaccines were also smaller. The post-vaccination allergy among persons whose pre-vaccination tuberculin induration was 9 mm or more to 1 TU RT 23 with Tween 80, did not increase by more than 4 mm after vaccination. While the group whose pre-vaccination tuberculin induration was below 9 mm, had an increase of post-vaccination allergy of a little over 8 mm. It is concluded that the allergy producing capacity of the Danish and Madras vaccines was not different.