Over the years there have been several rumors.
The confirmed ones include that:
-Hunters hunting infected primates and the blood, flesh, or part of the infected primate getting into the hunter.
-The butchering and eating of infected primates.
-And sadly, the mockery of simple humans; Bestiality. Truthfully this may be the cause in the true transfer. I do not wish to go into the topic. Easily put it's human and monkey interaction. AIDS is usually transfered in humans in such interactions.

There are also other rumors such as
-Unsterilized needles in Africa. (They could not afford it.)
-A polio medicine from SIV(which created HIV I believe[Don't remember]) infected kidneys.

Above all, the cure for AIDS can start with our knowledge of animals. Animal diseases Human diseases can always cause a whole new series of
incurable diseases. The search for AIDS should take a new turn but, heh, I'm not "important" enough to do so. Truthfully I'm only a kid with a new hypothesis, I'm not a genius, but I do believe my hypothesis may be correct. If someone can send this to AIDS researchers, I'd appreciate it.

Note-I do slightly care if you say you came up with this...
Just because I have a different opinion doesn't mean I can't feel jealous!

-A.W.