Perspectives on the futures of AIDS [editorial]

The acquired immunodeficiency syndrome (AIDS) has emerged as one of the most serious epidemics in modern times. Given an incubation period of 6 months-4 years and a prevalence rate of human T-lymphotropic virus type III (HTLV-III) of over 80% in certain high-risk groups a contined exponential increase in the incidence of AIDS can be expected. An additional 40000 cases of AIDS can be expected over the next 2 years in the US alone. It is hoped that prospective studies on the natural history of AIDS using serologic and virologic markers of HTLV-III will identify the factors responsible for the host response to infection. It must be learned whether an asymptomatic antigen-positive and/or seropositive individual will develop AIDS may years later or will continue to remain infectious. Another major issue is whether AIDS will remain confined to previously identified high-risk groups. However the very low prevalence of AIDS and HTLV-III infection in health care workers indicates that casual contact is not a risk factor for infection. The availability of a diagnostic test for HTLV-III now provides the capability of limiting transmission to recipients of blood and blood products. On the other hand it is unlikely that the incidence of AIDS due to sexual transmission will be affected until a vaccine oo effective treatment becomes available. Factors such as genetic susceptibility differences in virologic strains cultural differences regarding sexual practices co-infection with other pathogens and an altered immunologic status at the time of infection may all play a role in the subsequent development of AIDS. Exposure to immunosuppressive factors such as multiple sexually transmitted diseases or chronic parasitic infections may make certain individuals uniquely susceptible. These factors may result in an accumulation of effects that synergistically or additively lead to sufficient T-cell activation required for infection and continued viral replication.