Around two-thirds of humans are infected with one of the two herpes simplex viruses, HSV-1 or HSV-2. And a portion of humans have probably been plagued by this virus since we first became a species. According to new research, HSV-1 first jumped from chimpanzees to human ancestors some six million years ago, while HSV-2 first colonized our ancestor Homo erectus some 1.6 million years ago.
Researchers at University of California, San Diego, originally set out to determine why humans suffer from two different herpes viruses. Other primates, they say, just have one. To do that, they compared the genetic sequences of HSV-1 and HSV-2 to the sequences of eight herpes viruses that occur in primates. Using a powerful computer model that took into account the pressures of natural selection on viral evolution, they were able to approximate when HSV-1 and HSV-2 split from the primate strains based on similarities and differences in those viral genomes.
“Comparing virus gene sequences gives us insight into viral pathogens that have been infecting us since before we were humans,” the researchers said in a statement. In other words, when H. sapiens arrived on the scene a mere 200,000 years ago, herpes was waiting.