AIDS: During the 6th Conference on Retroviruses and Opportunistic Infections (CROI), researchers at the University of Alabama reported that they have traced the origin of AIDS to a subspecies of chimpanzees (Pan troglodytes) found in Africa. Studies of simian immunodeficiency virus (SIV), which is harmless in chimpanzees, may facilitate understanding about HIV transmission and the immune system response. Unfortunately the chimpanzees are being eradicated by hunters and the logging trade. Scientists speculate that these practices may spread SIV and other viruses further to the human population. More research is needed before information useful to the epidemic in humans is found.