Aids is caused by HIV, definately. There are other ways to destroy your immune system too. Using cocain whilst HIV infected makes the virus all coked out too and it replicates like crazy when cocain is present.

Also, AIDS is definately not man made but did come from primates. This doesn't mean Man hasn't used it to infect certain groups. This is a possibility, but it's a small one. I used to think that Africa was given aids to kill all the people there, but there is no evidance of this so it is quite irrational to even believe this..