Epidemiology of tuberculosis

In the United States, many people erroneously think that tuberculosis (TB) is a disease of the past--an illness that no longer constitutes a public health threat. In reality, TB is one of the leading global causes of morbidity and mortality. According to the World Health Organization, which compiles annual country profiles of reported TB cases using standardized case definitions, 2.4 million cases were reported in 2001. However, because of underreporting, the number of new TB cases is estimated to be 8.3 million, including 1.8 million deaths. In the United States, after more than 3 decades of steady downward trends, an unprecedented resurgence of TB occurred between 1985 and 1992. This increase was associated with deficient infrastructure, the human immunodeficiency virus (HIV) epidemic, immigration, outbreaks in congregate settings, and widespread occurrence of multidrug resistant TB strains. The resultant increased concerns provided the impetus for the development of a national action plan to combat MDR and the mobilization of new resources. Consequently, the incidence of TB cases has decreased from 1992 through 2002. New challenges are evident and must be addressed to achieve the agreed-on goal of eliminating TB in the United States. This report describes the global epidemiology of TB and the epidemiology in the United States, and outlines future challenges to the elimination of TB in the United States.