ABSTRACT
This chapter examines the immunologic and virologic mechanisms involved in the pathogenesis of human immunodeficiency virus type 1 (HIV-1) infection, and the interaction between the virus and the host. The natural history of HIV-1 infection varies considerably in terms of the pattern and rate of disease progression. The typical course of the infection is defined by three phases occurring over an 8- to 12-year period of time. Transmission of HIV-1 occurs by several different routes, including sexual contact, blood-to-blood contamination, and maternal-infant transmission. The most common route of infection is sexual transmission. Despite the variability in the natural history, the exposure to a sufficient virus inoculum is usually followed by the establishment of chronic HIV-1 infection. The experimental infection of rhesus monkeys with the simian immunodeficiency virus via the vaginal mucosa has produced insights into the sexual transmission of retroviruses. The role of genetic determinants in modulating the course of HIV-1 infection has been increasingly elucidated.
