ABSTRACT
Tuberculosis (TB) is an infection in humans due to either Mycobacterium tuberculosis (MTB) or Mycobacterium bovis. This disease has afflicted the human population since prehistoric times. In 1882, the tubercle bacillus was first described by Koch. At the turn of the century, TB was the leading cause of death in the United States. The history of tuberculosis in the twentieth century is notable for an initial decline in incidence due to improved living standards and isolation of infected patients, followed by the development of effective medical therapy in the late 1940s. In the mid 1980s, the incidence of TB infection in the United States began to rise after declining nearly 75% over the previous four decades. This rise was attributed to coinfection with HIV, decreased resources for TB control, immigration from high-prevalence countries, and outbreaks of TB in congregative facilities (homeless shelters, correctional facilities, crack houses, hospitals, nursing homes, and residential facilities for AIDS patients). Coupled with the rise in incidence of TB has been the emergence of multiple drug-resistant strains. The recent resurgence of TB in the mid-1980s led to increased efforts aimed at prevention of transmission, early diagnosis, and effective therapy, resulting in a gradual decline in TB incidence since 1992. In 1996, there were 21,337 reported TB cases in the United States, reflecting nearly a 20% decline since 1992 (Fig. 1).
