Human immunodeficiency virus (HIV)

AIDS is caused by the human immunodeficiency virus (HIV), a retrovirus of the lentivirus family that was unknown until the early 1980's, but since that time has been spread around the world to infect millions of persons. The result of HIV infection is relentless destruction of the immune system. All HIV infected persons are at risk for illness and death from opportunistic infectious and neoplastic complications as a result of the inevitable manifestations of AIDS. Retroviruses are unable to replicate outside of living host cells because they contain only RNA and and do not contain DNA. The variant of HIV that is the cause for almost all infections is known as HIV-1.