Ancient genetic study traces "cold sore" virus back 5,000 years
For people who get cold sores, the virus is with them for life – but how long has the virus itself been with humanity? Scientists from Cambridge have now sequenced the genome of the facial herpes virus, including samples taken from several ancient human remains, and found that it arose a few thousand years ago.
The herpes simplex virus 1 (HSV-1) is one of the most common viruses affecting humans, with as much as two thirds of the population infected. Most of the time it doesn’t bother its hosts, but occasionally will appear as a swollen lump on the lip, which can be contagious.
But how did such a common virus first appear? To find out, the team screened samples of viral DNA from ancient infected individuals, and compared them to more modern samples. Intriguingly, the researchers found only four examples of HSV-1 among the 3,000 archeological finds they screened.
The oldest was a 1,500-year-old adult male from the Ural Mountains, followed by an Anglo-Saxon woman from the 6th or 7th century. Next was a young man from around 700 years ago in the UK, and finally another man in the Netherlands who apparently died in 1672.
“By comparing ancient DNA with herpes samples from the 20th century, we were able to analyze the differences and estimate a mutation rate, and consequently a timeline for virus evolution,” said Dr. Lucy van Dorp, co-lead author of the study.
From this, the researchers were able to trace that the current HSV-1 strain arose in humans roughly 5,300 years ago. Exactly why it took off then can’t be confirmed, but the team suspects that it might be related to the hot new fad that is thought to have begun around the same time – kissing.
“Every primate species has a form of herpes, so we assume it has been with us since our own species left Africa,” said Dr. Christiana Scheib, co-senior author of the study. “However, something happened around five thousand years ago that allowed one strain of herpes to overtake all others, possibly an increase in transmissions, which could have been linked to kissing.”
This new study pushes the genetic data on the herpes virus back much further than previously known, which was only about 100 years. The team says that the next steps are to trace the origins of the virus back even further, including other hominins like Neanderthals.
The research was published in the journal Science Advances.
Source: Cambridge University