The herpes virus that commonly causes cold sores spread during the early Bronze Age migrations and may have been stimulated by the kisses that accompanied it, according to a new study. Apparently, the variant we have today surpassed all others around 5,000 years ago.
Cold sores are a common viral infection. They appear as small blisters on or around the lips, often grouped together in patches. They are passed from person to person through close contact such as kissing and are caused by the herpes simplex virus, which two-thirds of the population carry. Most cold sores heal in two to three weeks without scarring.
The virus has a history that dates back millions of years, with forms of it infecting various species, from corals to bats. Despite its contemporary prevalence in humans, scientists have struggled to find ancient examples of HSV-1, the most common type of herpes virus. Now, a new study by Cambridge researchers has struck herpes gold.
“Facial herpes hides in its host for life and is transmitted only by oral contact, so mutations occur slowly over centuries and millennia,” co-author Charlotte Houldcroft said in a statement. . “We need to carry out in-depth investigations to understand how DNA viruses like this evolve. Previously, genetic data on herpes only dated back to 1925.”
The researchers were able to track down herpes in the remains of four individuals, spanning a period of 1,000 years, and extract DNA from the roots of the teeth. At least two had gum disease and a third smoked tobacco. The oldest sample was from an adult male discovered in Russia around 1,500 years ago
Two other samples came from Cambridge, UK. A woman from an ancient Anglo-Saxon cemetery, dating from 6-7 centuries AD, and a young adult man from the late 14th century, buried in the grounds of a medieval hospital. The final sample came from a young adult excavated in Holland, probably killed by a French attack on his city in 1672.
DNA analysis of these four individuals showed that the herpes virus at the time was very similar to the virus seen today and may date back to the Bronze Age. The timing corresponds with the mass migration to Europe from the grasslands of Eurasia and population growth which is believed to have increased the rates of spread of the virus.
But there is another factor that could have come into play, the researchers said. The earliest known record of kissing comes from a South Asian manuscript from the Bronze Age. The kisses likely arrived with the westward migrations, providing a pathway for the virus to spread. Until then, herpes was transmitted from mother to child, limiting its spread.
“Every species of primate has a form of herpes, so we assume it has been around since our own species left Africa. However, something happened about five thousand years ago that allowed a strain of herpes to outpace all others, possibly an increase in transmissions, which could have been linked to kissing,” concluded co-author Christiana Scheib.
The study was published in the journal Scientists progress.