Epidemiology, evolution, and future of the HIV/AIDS pandemic

We used mathematical models to address several questions concerning the epi demiologic and evolutionary future of HIV/AIDS in human populations. Our an alysis suggests that 1) when HIV first enters a human population, and for m any subsequent years, the epidemic is driven by early transmissions, possib ly occurring before donors have seroconverted to HIV-positive status; 2) ne w HIV infections in a subpopulation (risk group) may decline or level off d ue to the saturation of the susceptible hosts rather than to evolution of t he virus or to the efficacy of intervention, education, and public health m easures; 3) evolution in humans for resistance to HIV infection or for the infection to engender a lower death rate will require thousands of years an d will be achieved only after vast numbers of persons die of AIDS; 4) evolu tion is unlikely to increase the virulence of HIV; and 5) if HIV chemothera py reduces the transmissibility of the virus, treating individual patients can reduce the frequency of HIV infections and AIDS deaths in the general p opulation.