Traces of disease found in prehistoric remains may rewrite the medical world’s understanding of syphilis and challenge the idea of its origins in the Americas, according to a new study.

Published in the International Journal of Osteoarchaeology in March, the study analyzed the 309 individuals, taken from 16 archaeological sites across Vietnam from 10,000 to 1,000 years ago.

Only the skeletal remains of three children (aged 18, five, and two-and-a-half years old) bore evidence of congenital (present at birth) treponematosis, a group of diseases that includes syphilis, yaws, bejel, and pinta.

The children’s remains, taken from the Man Bac site in northern Vietnam and An Son in southern Vietnam, dated to around 4,100 to 3,300 years ago, had distinctive dental abnormalities and skeletal lesions, indicating that the disease may have been congenital yaws, and not syphilis.

Researchers have for decades believed that of these diseases, only syphilis could be transmitted congenitally, lending to the assumption that syphilis began with Christopher Columbus’ journeys.

“Our research shows that this assumption may not always hold true,” explained study lead author Dr. Melandri Vlok of Charles Sturt University.  “Other treponemal diseases may also have been transmitted from mother to child.”

Previous research at Man Bac found that 10% of those buried in the area had most likely contracted treponemal disease.

Most of these, however, were seen in remains belonging to children and adolescents, in line with the known fact that non-venereal treponemal diseases are usually transmitted through skin to skin contact, rather than sexually.

“The epidemiology of the site strongly points toward a non-venereal form of treponemal disease,” Vlok said. “Yet we still see evidence of congenital transmission. That’s the surprising part.”

“If congenital transmission can occur in non-venereal treponematoses, then we need to rethink how we interpret skeletal evidence in the past. Some cases previously labelled as congenital syphilis may represent entirely different diseases.”

This “challenges one of the key pillars of the 'Columbus brought syphilis [to Europe from the New World]' theory and shows that … we're still a long way from solving the mystery of where syphilis really began,” Nicola Czaplinski, a doctoral candidate in health sciences at the University of Notre Dame Australia, said in an email to Live Science.