how did scientific awareness of hiv begin
HIV-1 is surprisingly old, and it probably debuted in humans at least three separate times -- one for each subtype, M, N, and O. Scientists' best guess is that the precursor of the most common M virus jumped from the Cameroon chimps to humans sometime before 1931.art One: Chapter Four Scientific Breakthroughs. HIV-1, which is responsible for the vast majority of AIDS cases worldwide, is divided into three groups -- the major group M, and the much rarer outlier group O and new group N -- that have diverged over years of mutation and evolution.