1981: AIDS is described in an issue of the Centers for Disease Control and Prevention's Morbidity and Mortality Weekly Report. 1984: AIDS identified as being caused by a human retrovirus, Human ...

If left untreated, human immunodeficiency virus (HIV) almost always will progress to AIDS, even after many years. The immune defenses become compromised and the body is less able to defend itself ...

In 1981, physicians in Los Angeles reported five young patients with Pneumocystis pneumonia, a rare lung infection later recognized as the first sign of HIV infection and a defining illness of AIDS.