HIV/AIDSWhat is HIV/AIDS?Acquired Immunodeficiency Syndrome (AIDS) is a severe disease that represents the late stage of infection with the Human Immunodeficiency Virus (HIV), which causes defective functioning of the body's immune system.
AIDS was first recognized in the U.S. in the early 1980s, when two unusual diseases (Karposi’s sarcoma, a type of cancer, and Pneumocystis carinii, an organism that causes pneumonia in people with impaired immune systems) began to appear in homosexual men. Since that time, our understanding of the disease has progressed rapidly, although measures to prevent the spread of the disease have lagged behind. It is not an understatement to say that AIDS is the most serious public health threat the world has seen in the past 50 years. There is no part of the U.S., or the world, for that matter, that can be considered "safe" from the threat of HIV and AIDS.
HIV is a virus of the type known as retroviruses. These viruses infect certain cells in the body, incorporating their viral genetic material into the cell’s own DNA. The body’s cells then begin to produce the virus, and in the process, may themselves be killed. In the case of HIV, this virus infects only selected cells in the body, of which the most important are certain infection-fighting white blood cells known as lymphocytes, specifically those lymphocytes known as "helper cells" (which can be identified because they carry a marker called "CD4"). HIV can also infect certain cells in the nervous system. Learn More
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