|Herpes viruses are as varied as they are old. There are more than 100 different kinds of herpes. Eight regularly infect humans, causing diseases like chickenpox and mononucleosis. Scientists had previously analyzed the herpes genome and created a viral family tree. Oral herpes, HSV-1, has been around since humans and chimpanzees split 6 million years ago. The researchers also discovered that HSV-2 must have jumped from ancestral chimpanzees into the human lineage later, as recently as 1.4 million years ago.|
In a model's most likely scenario, Paranthropus boisei infected a human ancestor called Homo erectus.