It turns out that herpes simplex virus 2—the penis/vagina/butthole kind with which 25 percent of American humans are currently infected—is a result of some ancient bestiality between our ancestors and chimpanzees, which lends a whole new meaning to "hot monkey love."
According to a new study, researchers found that HSV-1 (the cold sore kind) was already circulating before our evolutionary split with chimps 6 million years ago. However, HSV-2 in humans is the result of cross-species transmission, as it was transferred between chimps and human ancestors, such as Homo erectus, 1.6 million years ago.
After comparing human herpes viruses to those of primates, scientists were able to determine that primates and humans have their own versions of HSV-1, but that we share HSV-2.
"Understanding how and when we acquired viruses that currently infect us can give us perspective on future, potential cross-species transmission events that would lead to the introduction of new human viruses," said the study's author, Joel O. Wertheim, assistant research scientist at the University of California, San Diego AntiViral Research Center.