Scientists have long suspected that AIDS originated from wild chimpanzees, but until recently this was merely speculation. Both Nature and National Geographic report that simian immunodeficiency virus (SIV), a viral strain remarkably similar to human immunodeficiency virus (HIV), was discovered in wild chimpanzees of the sub species Pan troglodytes troglodytes in the jungles of the African country of Cameroon.
Previous to this discovery, there were reported cases of SIV in captive chimpanzees, but researchers knew they needed evidence from wild chimps to prove these apes were in fact a direct link to the human AIDS pandemic. Now they have it.
Beatrice Hahn of the University of Alabama at Birmingham, a key researcher on this project, thinks that it is likely that HIV in humans was contracted from SIV in chimpanzees when humans were exposed to chimp blood during the processing of hunted bushmeat.
Since HIV and SIV are so genetically similar, it is likely that humans contracted the virus from chimps who initially contracted it from monkeys rather than both humans and chimps contracting the virus directly from monkeys which was previously thought.