Archaeologists have revealed how infectious diseases such as the tropical disease yaws used to spread, underlining the threat of diseases such as COVID-19. The childhood disease yaws is capable of causing highly-infectious skin lesions, as well as affecting bone and cartilage.

The disease is spread through contact and can leave sufferers with severe disfigurement.

This shows us what happens when we don’t take action with these diseases

Melandri Vlok

And although the disease is easily curable in its early stages, the bone disfigurements are irreversible.

But despite yaws no longer being a medical concern in much of the world, it remains prevalent in the Western Pacific, affecting thousands of people.

Previous attempts to eradicate this tropical disease failed and a new attempt was ended by the coronavirus pandemic.

University of Otago scientist and PhD candidate Melandri Vlok incorporated archaeology evidence to highlight how diseases spread when different populations meet for the first time.

She focussed on what she calls the “friction zone”, where agricultural people met hunter-gatherers.

The archaeology expert specifically studied skeletal remains from the Man Bac archaeological site in Ninh Bình Province, Vietnam.

This has provided a treasure trove of data, due to the area’s role during the transition away from foraging to farming.

Remains recovered at the site have been well-studied but were not analysed for evidence of yaws.

Ms Vlok’s supervisor Professor Hallie Buckley had seen what she thought might be yaws on a photograph of Man Bac remains.

Later, Ms Vlok discovered a second example of the disease.

This was significant, as the archaeological site has been dated to be about 4,000-years-old.

There was no strong evidence for yaws in prehistoric Asia until now.

The landmark study suggests yaws was introduced to hunter-gathers in modern-day Vietnam by an agricultural population travelling from China.

These hunter-gathers originated from early Africans who also eventually moved into New Guinea, Solomon Islands and Australia.

The farmers had been in China for at least 9,000 years but it was not until around 4,000 years ago farming was introduced to Southeast Asia.

This migration most likely brought diseases, including yaws.

And the archaeologist believes the length of time the disease has existed in the region is important when considering how hard it has been to eradicate.

She said: ”This matters, because knowing more about this disease and its evolution, it changes how we understand the relationship people have with it.

“It helps us understand why it’s so difficult to eradicate.

“If it’s been with us thousands of years it has probably developed to fit very well with humans.”

And this year’s deadly COVID-19 pandemic has focused the world’s attention on the impact of infections diseases.

As a result, Ms Vlok believes valuable lessons are to be learned from the past.

She said: “Archaeology like this is the only way to document how long a disease has been with us and been adapting to us.

“We understand with COVID-19 today how fantastic that disease is at adapting to humans. And Treponema has been with us for so much longer.

“So, this shows us what happens when we don’t take action with these diseases.

“It’s a lesson of what infectious diseases can do to a population if you let them spread widely.

“It highlights the need to intervene because sometimes these diseases are so good at adapting to us, at spreading between us.”

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