Tuberculosis in children.

The World Health Organization estimates that 90 million cases of tuberculosis will occur throughout the world in the 1990s, and 30 million people will die from the disease. Although traditional epidemiology suggested that 90% of tuberculosis cases arise from reactivation of remote infection, urban studies in the United States using DNA fingerprinting techniques imply that up to 40% of current cases are due to recent acquisition, a finding that will alter some basic approaches to tuberculosis control. Drug resistance is emerging as a major obstacle to tuberculosis control in the United States and the world. New studies focusing on the genetic basis of drug resistance may lead to better diagnostic techniques and new drugs. New trends in treatment center on shorter but more intense and directly observed therapy to maintain adherence. The new emphasis in developed countries is to concentrate control efforts selectively on those individuals, with the greatest risk factors for development of tuberculosis infection and disease.