I don't know much about this, but I read that some primates have endemic SIV and don't get sick, whereas some other species of primate will die of AIDS after ex

I don't know much about this, but I read that some primates have endemic SIV and don't get sick, whereas some other species of primate will die of AIDS after exposure to SIV. For example, Wikipedia on SIV says that ~90% of female African green monkeys (vervets) have SIV, and don't get AIDS. From there one imagines that a primate species on first exposure to the virus has it as a deadly disease, but sometimes they evolve a resistance to getting sick from it, without eradicating the virus.