Ancient Vietnamese Remains Challenge Assumptions About Treponemal Diseases

A study led by Dr. Melandri Vlok from Charles Sturt University, alongside an international team from Australia and Vietnam, has unearthed evidence that suggests treponemal diseases may have been transmitted from mother to child thousands of years ago. This challenges the long-held belief that congenital transmission strongly indicates venereal syphilis.

The research, published in the International Journal of Osteoarchaeology, focuses on skeletal remains from children who lived in prehistoric Vietnam, dating between 4,000 and 3,200 years ago. It indicates that nonvenereal treponemal diseases, such as yaws, rather than venereal syphilis, could account for congenital infections in ancient populations.

Analysis of Skeletal Remains

Out of 309 individuals examined at 16 archaeological sites in Vietnam, only three children displayed diagnostic signs of congenital treponematosis, evidenced by distinctive dental abnormalities and skeletal lesions. This study highlights the importance of the site Man Bac in northern Vietnam, where previously noted high rates of treponemal disease were found among children and adolescents.

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

Implications for Understanding Syphilis Origins

The findings introduce significant implications for the historical discourse around syphilis. Researchers frequently relied on congenital infection evidence to argue the presence of syphilis outside of the Americas prior to Columbus’s voyages. However, Dr. Vlok noted that this new research suggests that congenital infection alone cannot definitively distinguish venereal syphilis from related treponemal diseases.

“If congenital transmission can occur in non-venereal treponematoses, then we need to rethink how we interpret skeletal evidence in the past,” Dr. Vlok added.

Challenges in Ancient Disease Research

The study also emphasizes the challenges in extracting ancient DNA, particularly in tropical climates like Southeast Asia, where the preservation of such DNA is often poor. Co-lead author Ms. Minh Tran, a PhD student from the University of the Philippines, Diliman, highlighted the ethical considerations surrounding destructive sampling of human remains.

“In tropical environments, recovering ancient DNA is incredibly difficult, and destructive sampling raises important ethical questions,” Tran emphasized, advocating for future research to engage more with the communities connected to these remains.

Revisiting the Evolution of Treponemal Diseases

The results suggest that the evolution of treponemal diseases is more intricate than previously understood. The team called for renewed focus not just on the origins of syphilis but also on the evolution of various treponemal diseases in correlation with human populations and changing environmental conditions.

“Treponemal diseases have a far more complex history than we once thought,” Dr. Vlok concluded. “Understanding that complexity is essential if we want to reconstruct how infectious diseases shaped human history, especially as diseases like yaws are re-emerging due to the climate crisis.”