Cold Sores Have Been Blistering Humans For Thousands of Years, Finds New Study

The ancient roots of the common herpes virus strain that causes cold sores have been uncovered through the preservation of DNA in human teeth dating back as long as 1,500 years.

According to genetic evidence, the 3.7 billion people who are currently infected worldwide by HSV-1 were first infected about 5,000 years ago. And may it have occurred at the same time as a brand-new, widely accepted cultural phenomenon: cuddling with one's significant other (or boos).

"Over the course of weeks and months, the whole globe has witnessed COVID-19 change quickly. Herpes is a virus that develops over a much longer period of time "explained University of Cambridge geneticist Charlotte Houldcroft of the UK.

"Since oral contact is the only way that facial herpes can spread and hide inside its host for life, mutations take place gradually over decades and millennia. To comprehend how DNA viruses like this develop, we need to conduct deep temporal research. Herpes genetic information was previously limited to 1925."

The herpes family has a lengthy and diverse history that spans several species and millions of years. Only eight of the 115 herpesviruses that we are now aware of infect people. The most prevalent of them is HSV-1, which is connected to cold sores. HSV-2, the strain linked to genital herpes, affects about 500 million individuals worldwide.

There is presently no known treatment for either of these types of infection, however outbreaks can be controlled and treated.

It has been a mystery as to how HSV-1 became the predominant human strain and is very hard to track. So a study team made the decision to dig deeper into prehistoric remnants.

Archaeologists have recently built libraries of the DNA extracted from ancient remains as DNA sequencing has grown speedier and less expensive. Researchers used these libraries to explore the ancient past for signs of HSV-1 and discovered that they were incredibly rare.

Only four herpes positives were discovered when ancient DNA samples from over 3,000 archaeological findings were processed, according to genomicist Meriam Guellil of the University of Tartu in Estonia.

Those four people lived over a period of a thousand years. The most recent was a young man who was killed in the Netherlands in 1672, most likely during a French invasion on his hamlet. He appeared to be a clay pipe smoker who smoked frequently based on the wear on his teeth.

Two of the people were from Cambridge, England. One of them was a young adult male who died in the late 14th century and was buried on the grounds of a charitable hospital from that time period. Significant indications of terrible dental abscesses were visible in his teeth. The second individual, a grown lady who lived and passed away in Cambridgeshire somewhere between the sixth and seventh century, likewise had gum disease visible in her dentition.

The oldest relics belonged to a Russian adult guy who lived and passed away about 1,500 years ago. Finding HSV-1 in people with gum disease, abscesses, or who smoked tobacco is not really unexpected because the virus often flares up when the patient has a mouth infection.

The scientists just needed only four instances in order to sequence the herpes DNA, compare the four cases, and calculate the rate of mutation for the current strain of HSV-1.

This produced a chronology that showed the current strain of HSV-1 emerged during the Bronze Age, following human migration from the grasslands of the Eurasian steppe into Europe and resulting in a population explosion.

Herpes is present in every species of ape, thus according to archaeologist Christiana Scheib of the Universities of Cambridge and Tartu, we may presume that it has been with us ever since our own species migrated out of Africa.

But something happened some 5,000 years ago that made it possible for one strain of the herpes virus to surpass all others, presumably an increase in transmissions that may have been brought on by kissing.

Romantic kissing has a hazy past, but prior studies have shown that it is not a universal human behavior. The same study discovered that the frequency of romantic kissing increased with a culture's degree of social complexity. It's probable that kissing also increased in popularity when humans moved, multiplied, and settled throughout the Bronze Age.

Tonsil hockey cannot be clearly traced back in time since there is no reliable means for doing so. Given the difficulties involved in finding the virus in prehistoric bones, even conclusions on the origins of HSV-1 are subject to substantial revision.

The researchers stated in their report that "our work underscores the necessity for more widespread coverage of current HSV-1, particularly in locations like Asia and Africa, along with additional observations supplied by aDNA samples."

Additional ancient genomes, such as those from the Neolithic era, "may further update our understanding of the evolutionary history of this presently ubiquitous virus and continue to enlighten on the nature of its connection with human hosts," according to the study.

The research has been published in Science Advances.