Heterosexual transmission of acquired immunodeficiency syndrome: international perspectives and national projections.

The heterosexual transmission of the acquired immunodeficiency syndrome (AIDS) has been documented in the United States by national surveillance data and heterosexual partner studies since the beginning of the epidemic. However, the efficiency of heterosexual transmission and related risk factors remain unclear. Viral transmission from males to their female sexual partners is well documented, although in the United States instances of female-to-male transmission have been observed less frequently. On the other hand, in parts of Africa and Haiti, AIDS appears to be a bidirectional, heterosexually transmitted disease that often occurs concurrently with other sexually transmitted diseases. Although a widespread heterosexual epidemic of AIDS could evolve in the United States, it seems more plausible that, like other sexually transmitted diseases, AIDS will settle in limited segments of the community characterized by certain high-risk behaviors.