The global epidemiology and projected short-term demographic impact of AIDS.

This paper summarizes the natural history, surveillance, and global patterns of infections with the human immunodeficiency virus (HIV), the etiologic agent of AIDS The focus is primarily on HIV-1 because surveillance of HIV-2, which has recently been recognized as a separate type of the virus, is only just beginning. The natural progress of the disease is described, from acute infection through asymptomatic phase to the clinical illness phase. Available evidence on the speed of progression from infection to AIDS and possible co-factors in that progression are reviewed. The 3 patterns of AIDS which are described characterize the experience of different regions according to the types of transmission ( i.e., homosexual versus heterosexual, contaminated blood, drug use) and demographic characteristics of the affected persons. An epidemiologically based short-term forecasting model for AIDS cases is presented and used to project the demographic impact of AIDS in a hypothetical central African country. In that hypothetical setting, the impact of AIDS is shown to be disproportionately felt in urban areas, where the projected increase in population will decrease by 30% due to AIDS deaths by 1997; the growth rate of the rural population will be only slightly affected. In conclusion, the global prevalence of the disease, and prospects and implications for the future are discussed. Without effective drugs for treatment and no vaccine for prevention of HIV infections, the short-term outlook is not good. HIV/AIDS is expected to be an increasing public-health problem in the next 2 decades.