Actually, back in the 1980s and I think even now that there are monkeys known to have the HIV virus but because their systems work differently than people they don't necessarily die from the disease. In fact, at one point it was believed that some people (In Africa and such)became infected by monkey bites. Just like with the bird flu some people believe that HIV and AIDs started as a cross species contamination.

somewhat, yes, in fact most HIV research is done with Chimpanzees, which are not easily infected but can be with a large viral load. There is also SIV, the monkey form of HIV, but monkeys have immune systems that are very effective in combatting the disease. Chimpanzees are used for HIV testing because there immune system is more like us, but their immune systems too are capable of fighting off the disease. As well, they have there own SIV(SIV-1). Why the human immune system is unable to fight off the disease is of high interest in the scientific community, as well as why most primates have the ability to fight off SIV( Simian Immunodeficiency Virus). An interesting question, is that species have their own version of SIV, and if they are infected by a form of SIV from another monkey there body has no defense, causing SAIDS (Simian acquired immunodeficiency syndrome. HIV-1 is believed to be from the SIV virus infecting chimpanzees, and many assumptions were drawn by the similarity of HIV-1 and SIV, while HIV-2 is believed to come from another form of SIV, a particular species of monkey from West africa, the soot mangabeys, this opens many intimate questions, for HIV-2 is very difficult to work with, I have had attempted to infect both chimpanzees and Rhesus monkeys with it unsuccessfully. HIV-1 does not seem to easily infect Simians, but enough of a Viral load, you can get the job done. There is also HSIV, a new disease created in the lab combining RNA, the amusing thing with HIV being that they have RNA with DNA intermediate, opposed to humans, who have DNA with RNA intermediate. Chimpanzees are very susceptible to infection from HSIV, and we believe it can infect humans easily(hard to find out, no volunteer subjects for some reason). As for non-primates, it seems that they can not be infected with either HIV, or SIV. There is also FIV (feline immunodeficiency virus), which shares many characterisitics with HIV and SIV but only infects felines. FIV is interesting because it shares almost no characteristics with other feline retroviruses, and shares many characteristics with HIV/SIV. Also, there has been an vaccine developed for FIV, that is moderately effective, though offering no protection against type A, it is effective for the other types. FIV is also unique for it is mainly spread by saliva, when cats fight, but HIV is not spread by saliva.