title: Origin of AIDS.
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000209:etiology* / Q000635:transmission; D000818:Animals; D002522:Chlorocebus aethiops; D017977:Deltaretrovirus / Q000302:isolation & purification*; D006801:Humans; D008251:Macaca; D012756:Sheep