Chimps May Have Survived ‘AIDS-Like’ Epidemic Two Million Years Ago, Dutch Researchers Report

Chimpanzees, which share more than 98% of their DNA with humans, may have survived an "AIDS-like" epidemic two million years ago, leaving them with a resistance to a virus similar to HIV, the AP/Philadelphia Inquirer reports. The hypothesis could explain why chimps carry the simian immunodeficiency virus, which is genetically similar to HIV, but are unaffected by the disease (Sterling, AP/Philadelphia Inquirer, 8/30). Study author Dr. Ronald Bontrop, who led a team of researchers from the Biomedical Primate Research Center in the Netherlands and the University of California, studied the DNA of 35 chimps and found that they share a "uniform cluster of genes" around the area that controls the immune system's defense against diseases. The lack of genetic diversity among the chimps suggests that an unknown "lethal sickness" attacked chimps long ago. Such a disease would have "wiped out all or almost all" of the chimps that did not have the "right immune system gene" to protect them from the virus, Bontrop said. With the knowledge that modern chimps are "largely immune" to HIV and SIV variants, the researchers theorized that an "AIDS-like" disease was to blame for the epidemic (AP/Minneapolis Star Tribune, 8/30). Chimps' immune systems seem to beat the immunodeficiency viruses by "targeting" the proteins of the virus that do not mutate. Bontrop said that humans who have been repeatedly exposed to HIV but who do not get sick may have similar defense mechanisms, suggesting that additional research needs to be conducted (AP/Philadelphia Inquirer, 8/30). Dr. Luis Montaner, an associate professor at the Wistar Institute in Philadelphia who was not involved with the study, said that the findings were "intriguing" but there is "no proof linking specific genes with resistance to AIDS in either chimpanzees or humans." The study will be published in the upcoming issue of the Proceedings of the National Academy of the Sciences (AP/Richmond Times-Dispatch, 8/30).