AN EPIDEMIOLOGIC MODEL FOR HIV AIDS WITH PROPORTIONAL RECRUITMENT

A model for HIV transmission is formulated for a homosexual population of varying size, with recruitment into the susceptible class proporti onal to the active population size and with stages of progression to A IDS. Analysis of this model includes identifying the threshold that de termines whether the disease dies out or proportions remain endemic an d establishing criteria that determine whether the population size dec ays asymptotically exponentially to zero or grows asymptotically expon entially to infinity. In an analogous heterosexual model, the conserva tion of heterosexual contacts is shown to imply that this two-sex mode l reduces to the one-sex model.