The epidemiology of tuberculosis in South Africa

Reports by reliable observers indicate that tuberculous disease did not occur to any great extent amongst South Africa's indigenous peoples prior to European colonization. Colonization introduced sources of infection and caused rapid urbanization for purposes of commerce and trade. By the start of the 20th century tuberculosis was recognized as a common health problem amongst the Black and Coloured peoples of South Africa. National notification commenced in 1921 and an incidence of 43 per 100,000 rose to 365 per 100,000 in 1958 and declined to 162 per 100,000 in 1986 before rising again to 221 per 100,000 in 1993. High incidences have been consistently recorded amongst the Coloured population of the Western Cape Province: in 1993 713 per 100,000 compared to the national incidence of 225 per 100,000. Using a computerized geographical information system the precise distribution of tuberculosis in two adjacent underprivileged, mainly Coloured communities, with a combined population of 34,000, is being studied. From 1985 to 1994 4044 notified tuberculosis cases gave an incidence of about 1200 per 100,000, varying from 78 to 3150 per 100,000 for the 39 enumerator subdistricts used for census purposes, and was highest in those with the lowest income. Of 5345 housing units 1835 (34%) housed at least one case of tuberculosis and 483 (9%) three or more cases. IS6110 DNA fingerprinting of strains from this community has shown a high degree of strain diversity (209 out of 334 strains evaluated). Clustering, indicative of recent transmission, was found in only 30% of isolates in this high tuberculosis incidence community.