Tuberculosis in Tanzania: A National sampling survey of drug resistance and other factors

Abstract

This survey was conducted in 1969/70 in a random sample of 15 of the 61 administrative districts in Tanzania. It included clinics with a long established tuberculosis service (A group), those with a tuberculons service of recent inception (B group) and those with no specialised tuberculosis service (C group), and 3 additional centres of special interest. The aim was to obtain, for tuberculous patients newly registered for treatment during a specified 6-month period, information on: 1.a) the proportions of patients with pulmonary and /or extra-pulmonary tuberculosis;2.b) the history of previous chemotherapy with antituberculosis drugs:3.c) the prevalence of bacteriologically-positive pulmonary tuberculosis;4.d) the prevalence of initial and acquired resistance to the standard antituberculosis drugs;5.e) the radiographic extent and type of disease and of cavitation.Of 1884 patients in the random sample, 87·4 per cent had pulmonary tuberculosis only, 2·5 per cent had pulmonary and extra-pulmonary tuberculosis and 10·1 per cent had extra-pulmonary tuberculosis only. Although there were differences in the proportions with extra-pulmonary disease in individual districts in each group there were no important differences in the average levels for the A, B and C groups. Of 256 extra-pulmonary tuberculous lesions in 237 patients, 58 per cent were lymph node, 26 per cent bone and joint and 12 per cent pleural, pericardial or peritoneal.Of 1694 patients with pulmonary tuberculosis with or without extra-pulmonary tuberculosis, 96·3 per cent gave no history of previous chemotherapy and 3·6 per cent a definite history. A sputum specimen from each of 1338 patients with pulmonary tuberculosis was examined by direct smear; 675 (50 per cent) were positive as were 694 (55 per cent) of 1257 cultures. For the patients with no history of previous chemotherapy the positivity rates were 59 per cent on smear and 66 per cent on culture for the A group, 53 per cent and 57 per cent for the B group and 35 per cent and 38 per cent for the C group.Of 636 patients with no history of previous chemotherapy and sensitivity test results, 9 per cent had a strain resistant to isoniazid and/or streptomycin. The total prevalence of resistance to isoniazid was 6 per cent and to streptomycin 4 per cent.Of 1278 patients aged 5 or more with a postero-anterior chest radiograph available and a diagnosis of intra-thoracic tuberculosis in Tanzania, 86 per cent were reported at an independent assessment in London as having a lung lesion. Among the 1171 patients of all ages reported as having a lung lesion, gross, extensive or moderate disease was present in 73 per cent of the radiographs and cavitation in 66 per cent. The type of radiographic disease was assessed as acute in 36 per cent, mixed-acute in 40 per cent, mixed in 19 per cent and chronic in 5 per cent.There was no evidence of associations between drug resistance and the extent or type of disease or presence of cavitation.The 3 additional centres of special interest were, with few exceptions, similar to the A group.