Human immunodeficiency virus (HIV) is a viral infection that progressively destroys white blood cells, weakening the immune system, which is the body's system of fighting infection. The final and most serious stage of HIV infection is acquired immunodeficiency syndrome (AIDS). According to the Centers for Disease Control and Prevention, more than 1 million people in the United States have HIV infection or AIDS. AIDS is a significant cause of non-traumatic death in the United States among people aged 25 to 44.

Show Full Description HIV is transmitted through contact with an infected person's body fluids, including blood, semen, vaginal secretions, cerebrospinal fluid, and breast milk. Although lower concentrations of HIV are found in tears, urine, and saliva, transmission of HIV from these fluids is extremely rare. HIV can be transmitted during sexual contact with an HIV-infected person or by receiving contaminated blood through a blood transfusion, by sharing needles, or from an accidental stick from an HIV-contaminated needle. HIV can also be transferred from an infected mother to her child during pregnancy, childbirth or in breast milk. HIV is not transmitted by casual contact or by close nonsexual interaction with someone at home, school, or work. Once human immunodeficiency virus (HIV) has entered the body, it attaches to a type of white blood cell called a lymphocyte. The HIV virus incorporates itself into the DNA of these cells and reproduces, releasing new viral particles and destroying healthy cells. This weakens the immune system. Once a person is infected with HIV, he or she can begin to transmit HIV to other people. Acquired immunodeficiency syndrome (AIDS) can develop within the first 1 or 2 years following HIV infection although it may take many years to develop. Symptoms of early HIV infection include persistent fever, rashes, swollen lymph nodes, and discomfort. While these symptoms typically resolve, the infected person can still spread HIV. In fact, individuals with HIV infection may feel well for several years before developing AIDS. Symptoms of AIDS include infections such as pneumonia, tumors, swollen lymph nodes, weight loss, fever, fatigue, diarrhea, and thrush. Treatment developments since the late 1990s have significantly improved the medical care of patients with HIV/AIDS. Diagnosis of HIV infection is done by testing blood or saliva. The information provided in the AIDS/HIV Condition Guide is not intended to be a substitute for professional medical advice. A licensed healthcare professional should be consulted for diagnosis of HIV infection or AIDS and treatment of any and all medical conditions.