As the epidemic of the acquired immunodeficiency syndrome (AIDS) in sub-Saharan Africa enters its second decade, much has been learned about the distribution and determinants of the disease and its causative agent, the human immunodeficiency virus (HIV). Over 6 million people, or 2.5% of the adult population, are thought to be infected with HIV. The distribution of HIV is largely determined by sexual behavior; as for other sexually transmitted diseases, the characteristics of sexual networks determine the extent and rate of spread of HIV. Female sex workers and their male clients are at high risk for HIV and have been important in initiating the epidemic in many African countries. The dynamics of HIV in the rest of the population are complex; men with multiple sexual partners are largely responsible for transmission of HIV to women in the general population. Other sexually transmitted diseases and lack of male circumcision may increase the probability of transmission of HIV during sexual intercourse and probably are partially responsible for the rapid diffusion of HIV in Africa. Interventions among high-risk groups are needed, but they must be accompanied by attempts to induce behavior change among men and women in the general population. Epidemiologic studies of the determinants of sexual behavior and sexual contact patterns, as well the design and evaluation of interventions, are urgently needed. Key areas for development are the study of behavioral exposures and outcomes, the evaluation of interventions, developing new methods for conducting interventions in resource-poor environments, and increasing the number of African scientists with the skills and resources to conduct epidemiologic studies.
PIP: A great deal has been learned over the past 2 decades about the distribution and determinants of AIDS and HIV in sub Saharan Africa. An estimated 6 million people, 2.5% of the adult population, are infected with HIV in the region. A World Health Organization model estimates 10 million will be infected in the region by 1994, and that Africa South of the Sahara, in which less than 9% of the world's population resides, will account for 60% of the global prevalence of HIV. This increase is projected despite recently observed increases in HIV prevalence in some parts of India and Thailand. The demographic, economic, and social impact of this widespread and growing infection will be staggering. Great variation in prevalence exists between countries and regions in Africa. It may be said, however, that the epidemic is mostly concentrated in large towns and cities, except for Uganda and western Tanzania where HIV is more disseminated. Peak HIV prevalence is found among those aged 15-45 years, with prevalence being comparatively higher among women. HIV has been transmitted in 80% of cases as a result of heterosexual activity; perinatal and blood transfusions each account for about 10% of cases. The characteristics of sexual networks especially determine the extent and rate of spread. Specifically, female sex workers and male clients are at high risk for infection and have been instrumental in starting the AIDS epidemic in sub-Saharan Africa. These men with multiple sex partners then transmit HIV to women in the general population. The presence of other sexually transmitted diseases and the lack of male circumcision may increase the probability of HIV transmission during sex and are probably partially responsible for the rapid diffusion of HIV in the region. Preventive interventions are needed among high risk groups and within the general population. Epidemiologic, behavioral, operational, and evaluation research are needed in order to design and implement programs which are most appropriate and effective in changing behavior.