Prior to the discovery of new treatments for AIDS, most people who were infected with HIV eventually developed full blown AIDS and most of these individuals died of this disease. However, there are some strains of HIV that are not as lethal as others, and scientists are attempting to understand variation in the virus and the ability of the immune system to respond to viral infection.
As the name HIV implies, the disease is known to be caused by a specific virus. Viruses are a curious type of phenomenon. In a sense, they are only partial organisms in that they must live inside another organism or host. Otherwise they are dormant. Moreover, their entire existence is focused on spreading from one host to another and on reproducing themselves.
When HIV enters a human body, it tends to seek out and attack a particular group of white blood cells commonly known as the T-helper cells. These cells are part of the body's immune system.
When the body is invaded by a pathogen, there is a rapid increase in the production of T4 cells, which is the body's signal that a pathogen is present and an immune response must be mounted for protection. Unfortunately, HIV interferes with this process.
When HIV encounters a T4 inside the blood system, it attaches itself and inserts its genetic code into the T4. In this way, the T4 is transformed into a biological factory that begins producing new HIV.
Ultimately, the T4 cell bursts, releasing new virus into the blood stream, and these, in turn, seek out other T4 cells to invade. In the process of its own reproduction, HIV destroys the ability of the body to fight infection, leading to illness and possible death.
HIV/AIDS has generated a considerable amount of controversy. Because the disease was first diagnosed in homosexual patients, some people assumed that it was somehow a peculiarly homosexual disease, perhaps a consequence of sexual or other practices common among homosexual men. This proved to be quite inaccurate. HIV is a blood-borne disease, meaning that the natural environment of the virus is human blood. Any behaviors that result in blood and other body fluids like semen or breast milk passing from one person to another can transmit the virus between people.