At present, human immunodeficiency virus (HIV) is thought fo have infected ouer 17 million people worldwide, over 1 million in North America and roughly 2 million in Latin America and the Caribbean. By comparison, infection with the tuberculosis (TB) agent Mycobacterium tuberculosis is far more common, current estimates indicating that roughly onethird of the world's population is infected. These two infections tend to aggravate each other. Thaf is, HIV leads to a progressive immune system

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... ssion that favors reactivation of TB in people with latent tuberculous infections; if promotes progression of TB primary infecfions or reinfections to full-blown tuberculous disease; and it fosters TB transmission, because those simultaneously infected wifh HIV and M. tuberculosis fend to develop a bacilliferous and contagious TB that can be transmitted to other susceptible individuals, even though the latter are HIV-negative. In addition, this coinfecfion fends fo promote circulation of drug-resistant M. tuberculosis and to produce peculiar manifestations that complicate TB diagnosis, treatment, and control. Overall, if seems clear fhaf the growing threat posed by these associated agents demands effective action in tke form of well-coordinated measures involving thoroughgoing participation by all countries. 312