Unrecognized "AIDS" in Monkeys, 1969-1980: Explanations and Implications

AIDS was recognized in humans in 1981 and a simian form was described in the years 1983 to 1985. However, beginning in the late 1960s, outbreaks of opportunistic infections of AIDS were seen in monkeys in the United States. This apparent syndrome went unrecognized at the time. We have assembled those early cases in monkeys and offer reasons why they did not result in earlier recognition of simian or human AIDS, including weaknesses in understanding disease mechanisms, absence of evidence of human retroviruses, and a climate of opinion that devalued investigation of infectious disease and immunologic origins of disease. The "epistemological obstacle" explains important elements of this history in that misconceptions blocked understanding of the dependent relationship among viral infection, immunodeficiency, and opportunistic diseases. Had clearer understanding of the evidence from monkeys allowed human AIDS to be recognized earlier, life-saving prevention and treatment interventions might have been implemented sooner.