Available data from longitudinal study (1961-68) from several different situations have been reviewed to understand the significance of patients showing radiological evidence of pulmonary tuberculosis without bacteriological confirmation. SITUATION IN GENERAL POPULATION: Few of the smear negative but X-ray active tuberculous patients (suspect cases) found in a survey of rural population done by National TB Institute, were culture positive (7-10%). On follow up for 18 months, only 3% of them became culture positive under conditions where intervention with specific treatment was absent or minimum. It is thus concluded that most of the cases diagnosed as active tuberculosis on the basis of single X-ray are not likely to be cases of tuberculosis. SITUATION AMONG SYMPTOMATICS ATTENDING HEALTH INSTITUTIONS: Data from the State TB Demonstration and Training Centres (STDTC) and the District Tuberculosis Programmes (DTP) have been presented. The New Delhi Tuberculosis Centre records (1970) show that only 27% of microscopy negative radiologically positive patients were confirmed on culture. For Bangalore and Agra STDTC, the proportions so confirmed were 20% and 25% respectively. It has been calculated that in the DTPs, not more than 30% of the microscopy negative radiologically positive patients could be the real cases of tuberculosis. In the DTP situation not more than 10% of the suspect cases may develop bacteriologically confirmed disease. Thus, not many of the suspect cases could be real cases of tuberculosis either on the basis of confirmation by culture or on the basis of development of bacteriologically positive disease in future.

Are the cases diagnosed ‘early’ by radiology? The hypothesis that X-ray discovers cases in the early stages has not yet been put to a scientific test. Further, the large differences even between experienced readers in interpreting X-ray shadows, render the method of X-ray diagnosis questionable. Is anti tuberculosis treatment of suspect cases warranted? The possible advantage of considering treatment of suspect cases as chemoprophylaxis has to be weighed against conservation of resources for treatment of infectious cases and the possible harmful effects of anti TB drugs to persons who are not suffering from tuberculosis.

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.

A study was designed to evaluate the outcome of holding sputum camps. The chest symptomatics referred by Peripheral Health Institutions (PHIs) to the camp were compared in terms of proportion of chest symptomatics registered and number of cases found with routine Case-finding actually carried out in the PHIs of an average District Tuberculosis Programme (DTP) and any educative effect of camp on the PHI staff. The study was carried out in 15 PHIs with wide range of performances in Case-finding. A team consisting of Medical Officer (MO), Treatment Organiser and Laboratory Technician of National TB Institute conducted sputum camps by involving the local staff and MOs of PHIs. The MOs of PHIs registered all the eligible symptomatics from the daily outpatients for a period of one month before the due date of the camp. The sputum was collected, slides prepared and patients advised to come on the camp date. A total of 528 chest symptomatics who reported at the PHIs during camp month were registered. Of them, 380 patients' sputum smears were prepared and 25 were found positive. Of the 528 symptomatics referred to the camp, only 86 (16.3%) actually turned up and 4 (16%) were positive. Prior to the sputum camp, 54 smear positive cases were diagnosed by these centres in 6 months. In the subsequent 6 months, 112 cases were diagnosed.

The study clearly shows that the efficacy of Case-finding by the sputum camp method is very low in comparison with integrated Case-finding at PHIs. More than 80% of the cases were missed by the camp by way of loss due to referral on the camp day. However, there was significant increase in the total number of cases diagnosed during 6 months after the camp, in comparison to 6 months prior to camp, thus, indicating the educative effect of the camp on the PHI MOs. The integrated sustained Case-finding activity in the PHIs cannot be substituted with the periodic Case-finding camps or holding of 'specialised clinics'.