In industrialized countries where AIDS is well established, HIV transmission has occurred primarily through male homosexual intercourse and blood-to-blood contact among IV drug abusers (Pattern I transmission, in UN/WHO parlance.) In sub-Saharan Africa, HIV is transmitted primarily through heterosexual intercourse, infecting women as often as men (Pattern H)(UN 1990:162-163). It is not coincidental that Pattern II countries are also characterized by high incidence and prevalence of standard sexually transmitted diseases (STDs) such as gonorrhea, syphilis, chlamydia, and chancroid. STDs, particularly those associated with genital ulceration, enhance the efficiency of HIV transmission (Greenblatt et al. 1988; Pepin et al. 1989; Mhalu 1990; Piot and Tezzo 1990; WHO 1990a; Prual, Chacko, and Koch-Weser 1991; Wasserheit 1992; Laga et al. 1993). In the words of Wasserheit (1992:61), "The interrelationships between human immunodeficiency virus (HTV) infection and other sexually transmitted diseases (STDs) are unique, complex, and intriguing. They probably explain, in part, the heterogenous faces of the HIV epidemic around the globe " Efforts to limit the heterosexual transmission of HIV in Africa must therefore address the high prevalence of other, standard STDs.