[Source: ScienceDaily] – The ancestors of the simian immunodeficiency viruses (SIVs) that jumped from chimpanzees and monkeys, and ignited the HIV/AIDS pandemic in humans, have been dated to just a few centuries ago. These ages are substantially younger than previous estimates, according to a new study from The University of Arizona in Tucson.
SIV has crossed over from chimpanzees and sooty mangabeys to humans at least eleven times, giving rise to several HIV lineages. Although HIV is a virulent pathogen in humans, SIV rarely causes disease in these species or the dozens of other African primate species it naturally infects. That these non-human primates typically remain unaffected after virus exposure has led to the hypothesis that there had been millions of years of coevolution between SIVs and their primate hosts.
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