The cause of AIDS is believed to be a virus that scientists isolated in 1983. The virus was at first named HTLV-III/LAV (human T-cell lymphotropic virus-type III/lymphadenopathy- associated virus) by an international scientific committee. This name was later changed to HIV (human immunodeficiency virus). HIV is passed on from the infected person to another person through the contact of body fluids such as blood, semen, vaginal fluid, breast milk and other body fluids containing blood. In other words, the virus may be transmitted through blood to blood and sexual contact, and from pregnant women to baby during pregnancy, delivery or breast feeding. Among health workers it has also been acquired through contact of cerebrospinal fluid surrounding the brain and the spinal cord, synovial fluid surrounding bone joints, and amniotic fluid surrounding a fetus. The virus starts weakening the immune system of the body making it more and more susceptible to various types of infectious attacks. Since these infections can easily attack the body of the AIDS patient they are often called the “opportunistic” infections. The infected person ultimately succumbs to one or more of them and dies. Although, the relationship between HIV and AIDS is not fully understood, available evidence suggests that the HIV is the cause of AIDS: HIV may remain dormant for as many as 8-10 years and develop into AIDS after that.

HIV research has produced certain ideas: (a) transmission of HIV is complex and uncertain; (b) HIV risk is subjectively defined; (c) the focus has to be on risk behaviour rather than group; and (d) there is a need for a new sociological paradigm.