Global aspects of tuberculosis in children.

Tuberculosis (TB) in children reflects the prevalence of the disease in adults as well as current transmission rates. Africa and South-east Asia have the largest number of tuberculosis cases and the situation there has been worsened by the HIV epidemic. Children born to HIV-infected parents, whether infected or not, are at high risk of developing tuberculosis because of the increased risk of exposure to the disease. Tuberculosis is more common among the disadvantaged and vulnerable groups in each society and the impact of overcrowding, under-nutrition and poverty is particularly severe on children. Recent studies have documented the increase in the occurrence of tuberculosis in children, both in developed and developing countries. The peak age of notification of tuberculosis decreases as the incidence of the disease increases in the region. Tuberculosis infection can progress rapidly to disease, particularly in infancy and early childhood. Most of the morbidity occurs in the first few years after infection. Recently infected children and those with large tuberculin reaction (>18 mm) are at increased risk for progression and should be followed closely. Mortality from tuberculosis is also highest in early childhood, mainly due to disseminated forms like meningeal and miliary tuberculosis. Tuberculosis can be controlled either by preventing the infection from occurring or by treating early infection after it has occurred. An efficient tuberculosis control program with early detection of infectious adults and their cure is the best long-term approach to the reduction of TB disease in children. The DOTS strategy advocated by the WHO has the potential to have a significant impact on the epidemiology of tuberculosis by achieving high cure rates and thereby decreasing community transmission. BCG vaccination, through effective against disseminated forms of the disease in childhood, has very little impact on adult forms of the disease. Chemoprophylaxis or preventive therapy is effective, but difficult to implement on a mass scale and is only recommended for special high-risk groups in developing countries.