Review of Recent Models of HIV/AIDS Transmission

Abstract

HIV, the human immunodeficiency acquired immunodeficiency syndrome virus, is the etiological agent for AIDS (acquired immuno deficiency syndrome). In 1982 Gallo suggested that the cause of AIDS was likely to be a new human retrovirus and, in 1983, researchers at the Pasteur Institute under the direction of Montagnier were able to isolate a new retrovirus from a New York AIDS victim (see Barre-Sinoussi et al., 1983). In 1984, Gallo and his colleagues isolated the same type of retrovirus and proved it to be the etiological agent of AIDS (for more details see Gallo, 1986, 1987; Wong-Staal and Gallo, 1985). This virus has been estimated to kill at least 30% of those infected. By April 1988, about 58,000 individuals have died of AIDS in the United States, and the Coolfont Report (1986) predicts that by 1991 the lower bound for the cumulative number of AIDS cases will be 290,000 individuals in the United States alone. One of the biggest problems associated with HIV is that most infected individuals appear to be asymptomatic and infectious for long periods of time, with an average infectious period of at least 8 years. Furthermore, there is growing evidence that the infectiousness of individuals varies with time since infection; the amount of free virus is relatively high just after infection (Francis et al., 1984; Salahuddin et al., 1984), remains low for several years, and climbs again within a year or so of the onset of AIDS (Lange et al., 1986).