In a study of human immunodeficiency virus type 1 (HIV-1)-uninfected African prostitutes, 83 (67%) of 124 seroconverted to HIV-1. Oral contraceptive use (odds ratio [OR], 3.1; 95% confidence interval [CI], 1.1-8.6; P less than .03), genital ulcers (mean annual episodes, 1.32 +/- 0.55 in seroconverting women vs. 0.48 +/- 0.21 in seronegative women; P less than .02) and Chlamydia trachomatis infections (OR, 3.6; CI, 1.3-11.0; P less than .02) were associated with increased risk of HIV-1 infection. Condom use reduced the risk of HIV-1 infection (OR, 0.11; CI, 0.05-0.27; P less than .0001). Stepwise logistic regression analysis confirmed independent associations between HIV-1 infection and oral contraceptive use, condom use, genital ulcers, and C. trachomatis. The presence of other sexually transmitted diseases may in part explain the heterosexual HIV-1 epidemic in Africa and may represent important targets for intervention to control HIV-1 infection.

To develop an HIV-1 vaccine with global efficacy, it is important to identify and characterize the viruses that are transmitted, particularly to individuals living in areas of high incidence. Several studies have shown that virus from the blood of acutely infected adults was homogeneous, even when the virus population in the index case was genetically diverse. In contrast to those results with mainly male cohorts in America and Europe, in several cases a heterogeneous virus population has been found early in infection in women in Africa. Thus, we more closely compared the diversity of transmitted HIV-1 in men and women who became infected through heterosexual contact. We found that women from Kenya were often infected by multiple virus variants, whereas men from Kenya were not. Moreover, a heterogeneous virus was present in the women before their seroconversion, and in each woman it was derived from a single index case, indicating that diversity was most likely to be the result of transmission of multiple variants. Our data indicate that there are important differences in the transmitted virus populations in women and men, even when cohorts from the same geographic region who are infected with the same subtypes of HIV-1 are compared.

Of 88,510 cases of acquired immunodeficiency syndrome (AIDS) reported in adults in the United States from 1983 through 1988, the percentage attributed to reported heterosexual contact with persons known to be infected or at increased risk of infection with human immunodeficiency virus (HIV) has increased steadily from 0.9 percent in the first quarter of 1983 to 4.0 percent in the fourth quarter of 1988, from 0.1 (in 1983) to 1.4 percent (in 1988) among men, and from 13 (in 1983) to 28 percent (in 1988) among women. Among women, the cumulative incidence of AIDS attributable to heterosexual contact per million population is over 11 times greater for Blacks and Hispanics than for Whites. Among men, this IntroductionEarly during the AIDS (acquired immunodeficiency syndrome) epidemic, there was considerable concern that AIDS would spread rapidly among heterosexuals in North America and Europe. These concerns were heightened by emerging evidence of heterosexual acquisition of AIDS in Africa. When the heterosexual AIDS epidemic did not rapidly materialize in industrialized countries, these concerns came to be regarded with skepticism. This paper provides an analysis of trends in the frequency and percentage of cases of AIDS in the United States thought to have been acquired heterosexually, together with a perspective on heterosexual transmission of HIV (human immunodeficiency virus) in the context of a general overview of heterosexually transmitted infections.

Objective.\p=m-\Factors that influence heterosexual transmission of the human immunodeficiency virus (HIV)