5,500-Year-Old DNA Shows Syphilis Has Deep Roots in the Americas

New DNA evidence from a 5,500-year-old human shin bone found in a Colombian rock shelter is quietly rewriting one of medicine’s longest-running mysteries: where syphilis came from. The study uncovered a close cousin of the bacterium that causes syphilis, showing that this family of pathogens was already present in the Americas thousands of years before Columbus set sail—and long before the disease exploded across Europe.

For generations, scientists have argued over whether syphilis was a “Columbian import” to Europe or an older, global problem. This discovery doesn’t give us every answer, but it does tilt the scales toward a more complex—and frankly, more human—story of how infections evolve and travel with us over millennia.

Archaeological cave site in Colombia where ancient human remains were analyzed for syphilis-related DNA
Archaeological work in a Colombian rock shelter led to the recovery of a 5,500-year-old shin bone containing DNA from a close relative of the syphilis bacterium. (Image credit: The Washington Post / reporting on recent research)

Why the Origins of Syphilis Have Been Such a Big Mystery

Syphilis is caused by the bacterium Treponema pallidum. It’s a sexually transmitted infection (STI) that can lead to serious heart, brain, and organ damage if it’s not treated. Today, we have reliable tests and effective antibiotics, but for much of history, syphilis was devastating, disfiguring, and deadly.

For more than a century, two main theories have competed:

  • Columbian hypothesis: Syphilis originated in the Americas and was brought to Europe by Columbus’s crew in the late 1400s, where it then spread rapidly.
  • Pre-Columbian hypothesis: Treponemal diseases (the broader family that includes syphilis, yaws, and bejel) were already present in the Old World long before Columbus, but may have looked different or been misdiagnosed.

Historical records from the 1490s describe a frightening new disease sweeping through Europe, often blamed on foreign enemies or sailors. But written descriptions and old bones alone can’t reveal which exact bacterium was responsible or where it truly began.

“Bones can tell us that someone suffered from a treponemal infection, but not automatically which one. Ancient DNA finally lets us peek behind that curtain and identify the precise relatives of Treponema pallidum that were circulating thousands of years ago.”

The New Study: A 5,500-Year-Old Shin Bone in a Colombian Cave

The latest research, reported by The Washington Post and published in a peer-reviewed journal, analyzed DNA from a human shin bone (tibia) uncovered in a rock shelter in Colombia. The remains are roughly 5,500 years old—long before European contact with the Americas.

Using advanced ancient-DNA techniques, scientists recovered genetic fragments from a bacterium closely related to modern Treponema pallidum. While it’s not identical to the strain that causes modern syphilis, it belongs to the same treponemal family—clear evidence that these infections have deep roots in the Americas.

Scientist working with ancient DNA samples in a modern laboratory
Ancient DNA analysis requires ultra-clean labs to prevent contamination. Researchers sequenced bacterial fragments preserved inside the 5,500-year-old bone.

The key take-away is that treponemal diseases were present and evolving in the Americas thousands of years ago. That doesn’t prove every detail of how syphilis spread to Europe, but it weakens the idea that the disease “suddenly appeared” only in the 15th century.


An Ancient Cousin, Not a Carbon Copy: How This Bacterium Relates to Syphilis

One important nuance: the bacterium found in the Colombian bone is a close cousin of modern syphilis, not necessarily the same strain that causes contemporary sexually transmitted infections.

Digital illustration of bacteria under a microscope
Modern syphilis is caused by Treponema pallidum pallidum, a spiral-shaped bacterium.
Ancient human bones laid out on an examination table for analysis
The Colombian find represents a more ancient branch in the treponemal family tree.

Treponemal diseases today include:

  • Syphilis – usually sexually transmitted.
  • Yaws – mainly affects skin and bones, spread by skin-to-skin contact, often in children.
  • Bejel (endemic syphilis) – spread through close nonsexual contact, often in arid climates.

The ancient Colombian bacterium seems to sit somewhere along this evolutionary spectrum. It suggests that, over thousands of years, treponemal pathogens have adapted to different climates, lifestyles, and transmission routes—sometimes primarily sexual, sometimes not.

“This isn’t about blaming one continent or another. It’s about understanding a long co-evolution between humans and bacteria. The more we learn about that history, the better prepared we are for the infections of the future.”

Does This Finally Settle the “Columbus Brought Syphilis” Debate?

The new findings add strong support to the idea that treponemal diseases were well established in the Americas long before European arrival. That leans toward, but does not fully settle, the classic Columbian hypothesis.

What we can say with reasonable confidence based on current evidence:

  • Treponemal bacteria were present in the Americas at least 5,500 years ago.
  • These ancient strains are close relatives of modern syphilis.
  • Historical records show a major syphilis outbreak in Europe in the late 1400s.

What remains uncertain:

  • Exactly when the sexually transmitted form of syphilis emerged.
  • Whether the explosive European outbreak was caused by a newly introduced strain from the Americas, a mutation of an existing Old World strain, or a mix of both.
  • How many different treponemal lineages were circulating worldwide before 1500.

Why This Matters Today: Lessons for Modern STIs and Public Health

It’s natural to wonder: beyond scientific curiosity, why should we care where syphilis came from thousands of years ago—especially when the bigger challenge is dealing with STIs in the here and now?

Here are a few reasons this discovery is more than just a historical footnote:

  1. It reminds us that infections adapt over time. The treponemal family has shifted forms and transmission routes across climates and cultures. That same evolutionary flexibility is what we see with modern pathogens, from antibiotic-resistant bacteria to emerging viruses.
  2. It challenges stigma and blame. For centuries, different countries and groups have blamed each other for “bringing” syphilis. The deeper we look, the clearer it becomes that infectious diseases are a shared human story—not a moral failing of any one people.
  3. It underscores the value of surveillance. If an ancient treponemal strain could eventually evolve into a severe STI, it’s a reminder that we need ongoing monitoring of how today’s pathogens are changing, too.

In clinics today, many people still feel shame or fear around STI testing. Knowing that these infections have been with us for millennia—and that they’re part of a long, complex evolutionary dance—can help reframe them as health conditions to manage, not moral judgments to hide from.


Practical Takeaways: Protecting Yourself from Syphilis and Other STIs

While scientists debate details of ancient DNA, the practical reality is straightforward: syphilis is still very much with us, and in many places, it has been on the rise over the last decade. The good news is that, unlike our ancestors, we have reliable ways to test, treat, and prevent it.

Evidence-based steps you can take:

  • Get regular STI testing if you are sexually active, especially with new or multiple partners. Many infections, including syphilis, can be silent for long periods.
  • Use barrier protection such as condoms or dental dams correctly and consistently to significantly reduce the risk of syphilis and many other STIs.
  • Seek care early if you notice unusual sores, rashes (especially on the palms or soles), or other symptoms after sexual contact. Early syphilis is usually very treatable with antibiotics.
  • Talk openly with partners about testing history, STI status, and protection. It can feel awkward, but it’s a powerful way to protect each other.
  • Ask your clinician about wider sexual health screening, including HIV, chlamydia, and gonorrhea, especially if you’re under 30, pregnant, or part of a group at higher risk.
Person consulting with a healthcare provider in a clinic
Modern testing and antibiotics make syphilis highly treatable, especially when it’s caught early.

Common Obstacles: Fear, Stigma, and Misunderstandings

In practice, the biggest barriers to controlling syphilis and other STIs are often emotional, not medical. Many people delay testing out of fear, shame, or past experiences of judgment in healthcare settings.

Some of the most common concerns people share:

  • “I’m afraid of what the test might show.” That anxiety is very human. But from a health perspective, knowing earlier almost always means more options, simpler treatments, and fewer long-term complications.
  • “I don’t want to be judged.” Well-trained sexual health providers understand that STIs are common medical conditions, not moral verdicts. If you’ve ever felt judged, it can help to seek out a dedicated sexual health clinic or a provider recommended by a trusted friend.
  • “I don’t have symptoms, so I must be fine.” Unfortunately, many STIs—including syphilis for long stretches—can be symptom-free or easy to overlook. Screening is still worthwhile even when you feel well.
“When I started working in sexual health, I quickly realized that the bravest people in the room were often the ones asking for a test. They weren’t ‘risky’ or ‘careless’—they were taking responsibility for their health and their partners’ health.”

What’s Next in Syphilis Research: Filling the Gaps in the Timeline

The Colombian find is unlikely to be the last word. Researchers are already searching for more ancient samples from:

  • Other parts of the Americas with well-preserved archaeological sites.
  • Pre-Columbian remains in Europe, Africa, and Asia that show bone changes consistent with treponemal disease.
  • Historical burials from the 14th to 17th centuries, to map how treponemal strains changed over time.

As more genomes are sequenced, scientists hope to:

  1. Pinpoint when the branch that leads to modern syphilis diverged from its ancient cousins.
  2. Understand which environmental or social changes (like urbanization, travel, or sexual networks) might have driven that shift.
  3. Identify genetic features that make some treponemal strains more invasive or more easily spread sexually.

A 5,500-Year Perspective: Reframing How We Think About Infection and Responsibility

The discovery of an ancient syphilis cousin in Colombia offers a humbling perspective. Long before ships crossed the Atlantic, long before antibiotics and blood tests, humans and treponemal bacteria were already entangled in a relationship that would shape bodies, histories, and even politics.

We may never know precisely when the first person developed what we would now call syphilis. But we can say this: infections are not new, and they are not about personal failure. They are about biology, behavior, and the environments we create together.

If you take one practical step from this ancient story, let it be this: consider making STI testing and open conversations about sexual health a normal, routine part of caring for yourself and the people you’re intimate with. It’s a small, concrete way of using the hard-won knowledge of the past to protect our shared future.

Action step: Before you close this page, take a moment to look up your local sexual health clinic or your primary care provider’s information, and note how to schedule a confidential STI screening if and when you need it. That bit of preparation can make it much easier to act when the time is right.