Acquired immunodeficiency syndrome, sexually transmitted diseases, and epidemiology. Past lessons, present knowledge, and future opportunities.

During the last decade, the field of sexually transmitted diseases has evolved from one with a primary concentration on gonorrhea and syphilis to one of expanded effort addressing a wide spectrum of organisms and syndromes. The emergence of the human immunodeficiency virus (HIV) has greatly accelerated the growth of public concern about sexually transmitted diseases and has provided momentum to epidemiologic research in the field. More than a year before HIV was accepted as the cause of acquired immunodeficiency syndrome, early epidemiologic studies led to public health actions which reduced viral transmission. Future research opportunities for epidemiologists will involve a greater behavioral emphasis and will evaluate primary prevention approaches within a variety of target populations.