"Cousins" of the HIV virus are millions of years old—not tens of thousands, as previous research has suggested, according to a new study. Researchers in Seattle examined HIV-like viruses in a range of primates. Genetic changes in monkey and ape immune systems point to the development of such viruses between five million and 12 million years ago, the BBC reports.
HIV-like viruses known as lentiviruses occur frequently in primates, and in the 20th century, a similar pathogen transitioned from chimpanzees to humans. "While primate lentiviruses may have modern consequences for human health, they have ancient origins in our non-human primate relatives," says a scientist.