Scientists at UAB today discussed a crucial missing link in the search for the origin of HIV-1, the virus responsible for human AIDS. That missing link is the natural reservoir of the virus, which the team has found in wild-living chimpanzees in southern Cameroon. Although researchers have long suspected that HIV-1’s origins lie in some way with chimpanzee infection through a closely related virus SIVcpz (simian immunodeficiency virus from chimpanzees), only a few captive apes had been found to harbor SIVcpz. In the study, UAB Professor of Medicine Beatrice H. Hahn, M.D., and her team conducted the first-ever molecular epidemiological survey of SIVcpz infection in wild-living chimpanzees in west-central Africa. By analyzing ape fecal samples collected by trackers from the forest floor in remote jungle regions of Cameroon, Hahn and her colleagues were able to detect SIVcpz-specific antibodies and nucleic acids (viral genetic information) in as many as 35 percent of chimpanzees in some ape communities. But how did it get from Cameroon to San Fransicsco, where humans with the disease were first decribed, and why the 25 year gap?