Childhood tuberculosis and tuberculous meningitis: high incidence rates in the Western Cape of South Africa

Abstract

In recent years higher incidence rates of tuberculosis (TB) have been reported from the Western Cape than from other health regions of South Africa. In contrast to the various pulmonary forms of tuberculosis, tuberculous meningitis (TBM) always requires hospital admission, and can thus be used as an indicator of the extent of the infection in a community, as well as providing a measure of the effectiveness of primary and secondary preventive measures. In the present study an attempt was made to identify all cases of tuberculous meningitis aged 14 years and younger which occurred in the region, by checking notifications and the records of all hospitals, and verifying diagnosis against set criteria. Rates for the entire period were calculated according to updated census data. There was a total of 689 confirmed cases, of which only 55% had been notified. Of the 238 cases confirmed in the 3-years period, 1985-1987, 25.2% were under 1 year, 51.7% under 2 years, and 79.8% under 5 years of age. Age-specific incidence per 100,000 children were respectively 31.5 (0-1 years), 17.1 (1-4 years), 4.8 (5-9 years), and 0.7 (10-14 years). Rates in rural areas were far higher than in metropolitan regions. Utilizing tuberculin test data and total notifications, the following risks could be calculated for 'Coloured' children (of mixed race) aged 0-4 years: 2-3% annual risk of infection; 15.7% risk of TB in infected population; 0.5% risk of TBM in infected population; 0.9% risk of TB in children aged 5-14 years; 0.01% risk of TBM in children aged 5-14 years.