Human Immunodeficiency Virus, commonly known as HIV, is a virus often transmitted throughthreatening. Despite persistent rumours that HIV originated in humans following an unknown individual having sexual intercourse with a chimpanzee, it is far more likely (according to Be In The Know) that chimpanzee meat was consumed. The first confirmed case of HIV appeared in 1959 in the Republic of Congo, but the endemic in the US is believed to have begun around the mid-1970s.