Researchers make it clear that these are just theories, and that there’s currently no way of proving that they’re true.
Herpes is spread through contact with sores and saliva. Kissing, basically. Researchers now theorize that what may have kickstarted herpes’ spread is the adoption of kissing popularized during the Bronze Age.
Their findings, published in the journal Science Advances, is based on the DNA of the first ancient specimens of herpes. After analyzing, they discovered that the dominant variant of herpes today made its takeover 4,500 years ago.
“The variants around in Europe today all share an ancestor in the bronze age,” Dr. Charlotte Houldcroft, one of the studies’ virologists, told The Guardian. “There were variants around before that, but those have been replaced, probably because of human behavior.”
Researchers analyzed 3,000 different historical gravesites and found only four subjects with herpes infections. These subjects varied widely in locations and eras, with one belonging to the Iron Age in the Ural mountains, another to a village on the bank of Rhine from the 1600s, and more.
Researchers believe herpes started spreading when people started kissing after westward migrations — from Asia to Europe — brought the custom across the globe. Before that, kissing wasn’t ubiquitous, with the first record of it appearing on a Bronze Age manuscript from south Asia. Before these migrations, researchers believe herpes was transmitted from mothers to their children.
“If you suddenly have a group of people who are kissing, which was not a universal human behavior, that is an extra way to spread the virus,” explains Houldcroft.
Still, researchers make it clear that these are just theories, and that there’s currently no way of proving that they’re true. “Only genetic samples that are hundreds or even thousands of years old will allow us to understand how DNA viruses such as herpes and monkeypox, as well as our own immune systems, are adapting in response to each other,” said Houldcroft. Speculating is very fun though.