In May, after decades of speculation, researchers isolated what they pegged as the origin of AIDS. The team, led by Beatrice Hahn, MD, of the University of Alabama, made the discovery in chimp feces in the African nation of Cameroon—and scientists worldwide went ape shit. Experts had long believed that the simian immunodeficiency virus (SIV) mutated into HIV-1 (responsible for the vast majority of global infections) after African hunters ingested or were bitten by infected chimps. But they couldn’t isolate an SIV strain similar enough to prove the point. Unlike its human counterpart, SIV does not attack chimp immune systems. “We found two strains that are dead ringers for HIV-1,” Hahn told POZ. “If we can compare the two, we can see what is species specific and understand why HIV-1 is so pathogenic.”

Conspiracy theories about HIV—that it started, say, as a genocidal government plot—abound globally. Will this silence such speculation? “Dr. Hahn has exaggerated her findings’ significance,” says Edward Hooper, whose book The River contends that HIV spread to humans in the ’50s through an experimental polio vaccine derived from infected chimp kidneys. “She has not found the source. The two viruses are close, but not that close.” Says Hahn, “People will believe what they want. It is not my responsibility to convince them. I just put out data.” Let the chest beating begin.