Distribution of tuberculin test indurations were studied in relation to nutritional status of 930 rural children aged 1-4 years and 796 aged 5-9 years. Using Quetlet's Index, it has been observed that the distribution of indurations were similar in normal and malnourished children. By following Jelliffe's criteria of grading nutrition, no correlation was observed between the size of induration and degree of malnutrition. It is concluded that malnutrition in the community may not influence the prevalence rates of tuberculin infection based on such testing.

Under the District Tuberculosis Programme, the key personnel at the District Tuberculosis Centre are expected to supervise the Peripheral Health Institutions (PHIs) periodically in order to assess and improve the programme activities. A supervision form is used for the purpose of recording the observations made during supervisory visits. This procedure is subjective and does not offer an objective assessment. In this paper, an objective scoring method has been described for supervision of PHI laboratories. The total score suggested is 200 which is apportioned as follows: cleanliness-15, registration & recording-35, sputum collection-10, smear preparation-30, staining-35, microscopy-35, and maintenance of microscope-40. Each category in turn is subdivided according to specific task performed. Minimum satisfactory score is 75% for each topic individually. High level of efficiency is thus recommended, as microscopy is the mainstay in casefinding of tuberculosis. A similar scoring procedure can also be used at the State TB Centre for the purpose of supervising the DTCs. However, this is only a quality control procedure and does not reflect the quantum of work.

One of the hypothesis put forth for the failure of BCG vaccine to show protection against bacillary pulmonary tuberculosis in Chingleput trial was the interference from non-tuberculous mycobacteria that were prevalent in the trial area. In order to test this, a study was conducted with the following objectives: to investigate (1) Protection given by BCG and M.avium intracellulare (MAI) which is the most prevalent species, against the challenge with high and low virulent strains of M.tuberculosis in sensitised guineapigs. (2) Whether M.avium Intracellulare (MAI) interferes with the protective effect of BCG against challenge with both high and low virulent strains of M.tuberculosis. Sensitization was done with MAI in guineapigs using both oral and intradermal routes. Groups of species were immunized with BCG/Placebo and later challenged with high/low virulent strains of M.tuberculosis. Colony counts of M.tuberculosis bacilli from spleens of the animals were done to measure the protective effect.
The findings were: (1) BCG showed protection against both high and low virulent challenges. (2) MAI in both oral and intradermal routes had no effect against low virulent challenge. (3) There was no significant interaction between BCG and MAI against low virulent challenge. (4) MAI when given orally, showed a significant protection against high virulent challenge. The same was not seen with intradermal route. (5) MAI orally, interfered with the protective effect of BCG against high virulent strains of M.tuberculosis.

South Indian Variant strain of M.tuberculosis has been found to be less virulent to guineapigs through various studies from Madras and Bangalore. It was not known whether the low virulent nature of the tubercle bacilli was a fixed character or a change due to serial passages inside the body over a period of time. Hence, a study was conducted to see the behaviour of low virulent tubercle bacilli over a period of eight years during twenty passages in animals.

Ten low virulent cultures of M.tuberculosis isolated from patients belonging to Bangalore area were injected intramuscularly into guineapigs. The extent of lesions was assessed through Mitchison's Virulence scoring method. Bacilli recovered from the spleen of these guineapigs were passed into another set of animals and virulence scored. Twenty serial passages were thus performed over a period of eight years. The findings revealed that throughout the study in all the passages, the south Indian Variant of M.tuberculosis maintained its low virulent character.