How does HIV cause AIDS?
HIV destroys a certain kind of blood cell (CD4+ T cells) which is crucial to the normal function of the human immune system. In fact, loss of these cells in people with HIV is an extremely powerful predictor of the development of AIDS. Studies of thousands of people have revealed that most people infected with HIV carry the virus for years before enough damage is done to the immune system for AIDS to develop. However, sensitive tests have shown a strong connection between the amount of HIV in the blood and the decline in CD4+ T cells and the development of AIDS. Reducing the amount of virus in the body with anti-retroviral therapies can dramatically slow the destruction of a person’s immune system. For more information view How HIV causes AIDS (National Institute for Allergy and Infections Diseases, NIH).
HIV destroys CD4+ T cells that are important to the normal function of the human immune system. As the virus destroys these cells, HIV-positive people are susceptible to illnesses that generally do not affect people with healthy immune systems. According to studies including thousands of people, most HIV-positive people are infected with the virus for years before it does enough damage to the immune system to make them susceptible to AIDS-related diseases. Tests are available to measure the amount of HIV in the blood the viral load and those with higher viral loads are more likely to develop AIDS-related diseases and to experience a decline in their CD4+ T cells. Reducing the amount of virus in the body with antiretroviral medications can dramatically slow the destruction of a person’s immune system and the progression of illness.
HIV is transmitted mostly through semen and vaginal fluids during unprotected sex without the use of condoms. Globally, most cases of sexual transmission involve men and women, although in some developed countries homosexual activity remains the primary mode. Besides sexual intercourse, HIV can also be transmitted during drug injection by the sharing of needles contaminated with infected blood; by the transfusion of infected blood or blood products; and from an infected woman to her baby, before birth, during birth or just after delivery. HIV is not spread through ordinary social contact; for example by shaking hand, travelling in the same bus, eating from the utensils, by hugging or kissing. Mosquitoes and insects do not spread the virus nor is it water-borne or air-borne.
HIV destroys a certain kind of blood cell CD4+ T cells (helper cells) which are crucial to the normal function of the human immune system. In fact, loss of these cells in people with HIV is an extremely powerful predictor of the development of AIDS. Studies of thousands of people have revealed that most people infected with HIV carry the virus for years before enough damage is done to the immune system for AIDS to develop. However, recently developed sensitive tests have shown a strong connection between the amount of HIV in the blood and the decline in CD4+ T-cell numbers and the development of AIDS. Reducing the amount of virus in the body with anti-HIV drugs can slow this immune destruction.
