Introduction
Since it was first documented in 1981 by the Centers for Disease Control and Prevention, acquired immune deficiency syndrome (AIDS) has claimed more than 25 million lives worldwide. French scientists discovered the virus that causes AIDS, human immunodeficiency virus (HIV) two years later. There have been significant advances in treatments for the virus, but a cure has yet to be found. HIV devastates the body's immune system, leaving sufferers vulnerable to many illnesses that otherwise would not pose a significant threat. A person is diagnosed with AIDS when he develops one or more of certain infections or cancers associated with the virus. The disease has four stages.
Stage 1: Initial HIV Infection
A person is infected with the HIV virus through the exchange of body fluids---semen, blood, vaginal fluid or breast milk---with an infected person. The initial stage of the infection generally includes flu-like symptoms and lasts several weeks. There is a large amount of HIV in the blood and the immune system tries to fight the virus by producing HIV antibodies.
Stage 2: Asymptomatic Period
After the initial infection, the HIV virus appears to go away. For a period that can last as long as 10 years, there are no further symptoms other than occasional swollen glands. The HIV level in the peripheral blood drops to an extremely low level, but in truth, the virus is far from dormant. It is very active in the lymph nodes, which contain white blood cells and are critical to the proper function of the immune system.
Stage 3: Symptomatic Period
Eventually, the immune system becomes so damaged by HIV that it begins to fail, leaving the body open to infections and cancers the immune system normally would prevent. This occurs for three primary reasons: the lymph nodes are exhausted from fighting HIV; the virus itself mutates and becomes stronger and more varied, leading to the destruction of more T cells (white blood cells that fight infection); the body is no longer able to keep up with replacing lost T cells.
Stage 4: Full-blown AIDS
As the immune system fails, the infections and cancers that occur become more and more serious. Ultimately, a person with HIV is diagnosed with AIDS when she develops one or more serious infections or cancers commonly associated with the virus, such as Kaposi's sarcoma, non-Hodgkin lymphoma, pneumocystis, Jirovevecii pneumonia, herpes simplex or toxoplasmosis. Her T cell count also must reach a certain very low level.
Tags: immune system, , with virus, AIDS when, AIDS when develops, associated with