Tuberculosis in Kenya: a second national sampling survey of drug resistance and other factors, and a comparison with the prevalence data from the first national sampling survey. An East African and British Medical Research Council Co-operative Investigation.

A survey was carried out in 1974 in the same random sample of 11 of 30 districts in Kenya that were surveyed in 1964, to obtain information on (a) the proportion of patients with pulmonary and with extra-pulmonary tuberculosis, (b) the prevalence of bacteriologically-positive pulmonary tuberculosis, (c) the prevalence of initial and acquired drug resistance, (d) the radiographic extent and type of pulmonary disease, and (e) the changes that had occurred in the 10-year period. Of 1490 patients, 88.5% had pulmonary tuberculosis only, 3.0% had both extra-pulmonary and pulmonary tuberculosis and 8.6% had extra-pulmonary tuberculosis only. Of the 172 patients with extra-pulmonary tuberculosis, 51% had lymph node involvement, 24% bone and joint disease and 9% a pleural effusion. Of the 1362 patients with pulmonary tuberculosis (with or without extra-pulmonary tuberculosis) 94% had no history of previous chemotherapy, fewer than 1% a history of possible and 6% a history of definite previous chemotherapy. (The proportions for the patients with extra-pulmonary tuberculosis only were 94%, 1% and 5% respectively.) A sputum specimen was produced by 1096 (80%) of the patients with pulmonary tuberculosis; 69% of smear results were positive, as were 74% of the culture results. In 2 (0.25%) of the 807 patients with a positive culture the strain was identified as being neither M. tuberculosis nor M. bovis. Of 702 patients with no history of previous chemotherapy and a sensitivity test result available, 10.1% had a strain resistant to isoniazid and/or streptomycin, 7.3% to isoniazid alone, 1.4% to streptomycin alone and 1.4% to both drugs. Of 1133 patients with chest radiographs available and a diagnosis in Kenya of pulmonary tuberculosis, a lung lesion or a pleural effusion was reported at independent assessment in London for 91%. Gross, extensive or moderate disease was present in 73% of the patients and cavitation was present in 72%. The radiographic disease was classified as acute in 31%, mixed-acute in 52%, mixed in 12% and chronic in 5%. The disease in children was usually less extensive, less often cavitated, and more acute than in adults. A comparison of the prevalence data in 1974 with that in 1964 suggested that there was a modest decline in the incidence of tuberculosis but that the characteristics of the registered patients and their disease were very similar in all respects; the disease was just as extensive radiographically and cavitation was, if anything, more common and more extensive in 1974 than in 1964.