Scientists have discovered the evolutionary origins of human herpes: chimpanzees. Researchers at the University of California, San Diego School of Medicine have found the evolutionary origins of human herpes simplex virus (HSV) -1 and -2. They found that HSV-1 infected hominids before their evolutionary split from chimpanzees about 6 million years ago, while HSV 2 jumped from primitive chimpanzees to ancestors of present humans about 1.6 million years ago.
"The results help us to better understand how these viruses evolved and found their way into humans. Animal disease reservoirs are extremely important for global public health. Understanding where our viruses come from will help guide us in preventing future viruses from making the jump into humans." said Joel O. Wertheim, PhD, assistant research scientist at the UC San Diego AntiViral Research Center and lead author of the study, in a news release.
Herpes simplex virus has infected about two-thirds of the human population. The virus commonly affects as cold sores on the mouth or as blisters on the genitals. It has been found that humans are the only primates infected by two herpes simplex viruses.
Researchers, in order to learn more about the virus, compared both herpes virus 1 and 2 genes sequence to simplex viruses from eight ape and monkey host species. With the use of advanced molecular evolution models, the researchers estimated the viral divergence among ancient and modern animals. This technique allowed them to find out when HSV-1 and HSV-2 were first introduced into humans.
"The results help us to better understand how these viruses evolved and found their way into humans. Animal disease reservoirs are extremely important for global public health. Understanding where our viruses come from will help guide us in preventing future viruses from making the jump into humans." said Joel Wertheim, one of the researchers.
The researcher concluded that HSV-2 was more genetically related to the herpes virus found in chimpanzees. This discovery indicated that humans must have acquired HSV 2 from a modern chimp ancestor around 1.6 million years ago, prior to the evolution of modern humans around 200,000 years ago. On the contrary, HSV-1 has been present in humans for far longer.
"Comparing virus gene sequences gives us insight into viral pathogens that have been infecting us since before we were humans," Wertheim added.
