29 July 2022
The first ancient genomes from the virus behind cold sores to be sequenced suggest a Bronze Age flourishing that saw modern strains of the disease start to go global.
Ancient genomes from the herpes virus that commonly causes lip sores – and currently infects some 3.7 billion people globally – have been uncovered and sequenced for the first time by an international team of scientists led by the University of Cambridge.
The latest research suggests that the HSV-1 virus strain behind facial herpes as we know it today arose around 5,000 years ago, in the wake of vast Bronze Age migrations into Europe from the Steppe grasslands of Eurasia, and associated population booms that drove rates of transmission.
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Herpes has a history stretching back millions of years, and forms of the virus infect species from bats to coral. Despite its contemporary prevalence among humans, however, scientists say that ancient examples of HSV-1 were surprisingly hard to find.
New cultural practices
The authors of the study, published in the journal Science Advances, say the Neolithic flourishing of facial herpes detected in the ancient DNA may have coincided with the advent of a new cultural practice imported from the east: romantic and sexual kissing.
“The world has watched COVID-19 mutate at a rapid rate over weeks and months. A virus like herpes evolves on a far grander timescale,” said co-senior author Dr Charlotte Houldcroft, from Cambridge’s Department of Genetics.
“Facial herpes hides in its host for life and only transmits through oral contact, so mutations occur slowly over centuries and millennia. We need to do deep time investigations to understand how DNA viruses like this evolve,” she said. “Previously, genetic data for herpes only went back to 1925.”
The four individuals studies
The team managed to hunt down herpes in the remains of four individuals stretching over a 1,000-year period, and extract viral DNA from the roots of teeth. Herpes often flares up with mouth infections: at least two of the ancient cadavers had gum disease and a third smoked tobacco.
The oldest sample came from an adult male excavated in Russia’s Ural Mountain region, dating from the late Iron Age around 1,500 years ago.
Two further samples were local to Cambridge, UK. One was a female from an early Anglo-Saxon cemetery a few miles south of the city, dating from 6-7th centuries CE. The other was a young adult male from the late 14th century, buried in the grounds of medieval Cambridge’s charitable hospital (later to become St. John’s College), who had suffered appalling dental abscesses.
The final sample came from a young adult male excavated in Holland: a fervent clay pipe smoker, most likely massacred by a French attack on his village by the banks of the Rhine in 1672.
The researchers point out that the earliest known record of kissing is a Bronze Age manuscript from South Asia, and suggest the custom – far from universal in human cultures – may have travelled westward with migrations into Europe from Eurasia.