The HIV Virus

HIV is the virus that causes AIDS and, as with all viruses, a cure has not been found. Once inside the body, HIV viral particles invade CD4 lymphocytes (a group of white blood cells that normally help guard against attacks by bacteria, viruses and other germs by coordinating the immune system) and use the cell's own genetic material to produce billions of viral copies. Foreign infected cells are usually easily recognised by the body. In people with HIV the infected cells are recognised by the body as it's own cells and therefore are not destroyed. For the newly manufactured HIV particles to enter the bloodstream and infect more CD4 cells, they must first lyse or burst the infected CD4 cell. In this way, the cycle of HIV infection continues, and the total number of normal CD4 cells decreases progressively from the time of infection with HIV.

Eventually, the number of CD4 cells - the main signallers and coordinators of the immune system - drops below the threshold level needed to defend the body against opportunistic infections. The body becomes vulnerable to many different types of opportunistic infections (infections that have an "opportunity" to invade the body because its immune defences are weak). HIV infection also increases the risk of certain malignancies (cancers), neurological illnesses (illnesses of the brain and nerves), body wasting and death. The entire spectrum of symptoms and illnesses that can happen when HIV infection significantly depletes immune defences is called AIDS (acquired immunodeficiency syndrome).