From San Francisco, at the 11th Conference on Retroviruses and Opportunistic Infections
Viruses related to HIV can be found in the blood of some zoo staff and other people who work with primates, although the infections don't appear to be harmful.
"Simian retroviruses are actively crossing into human populations," says Walid M. Heneine of the Centers for Disease Control and Prevention in Atlanta.
HIV, a retrovirus with several variants, evolved from simian immunodeficiency virus (SIV). Other retroviruses known to infect primates include simian type D retrovirus, simian T-cell lymphotropic virus, and simian foamy virus (SFV).