It’s hard to wrap your head around the sheer scale of the devastation smallpox caused. Before it was officially declared eradicated in 1980, this virus—Variola—was basically the bogeyman of human history. It didn't care if you were a peasant in a rice paddy or a king in a palace. It just killed. But for a long time, scientists were actually stumped by the most basic question of all: where did smallpox originate? We knew it was old, sure. We saw the scars on Egyptian mummies. But the "when" and the "how" were slippery.
Honestly, the timeline of smallpox is a bit of a detective story. For decades, the narrative was that it had been haunting us for ten thousand years, maybe since the dawn of agriculture. But recent genetic breakthroughs have flipped that script. It turns out the virus might be much younger than we thought, even if its ancestors are ancient.
The Egyptian Evidence: Scars Across Millennia
When you look at the physical evidence, Egypt is usually the first stop. If you’ve ever seen photos of the mummy of Ramses V, who died around 1145 BCE, you’ll notice something unsettling. His face and neck are covered in pustular eruptions. They look exactly like smallpox scars.
For a long time, this was the "smoking gun." Researchers like Donald Hopkins, a giant in the field of disease eradication, pointed to these mummies as proof that smallpox was already a major player in the ancient world. It wasn't just Ramses, either. Other mummies from the 18th and 20th dynasties show similar skin lesions.
But there’s a catch.
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DNA doesn't survive well in the heat of the Egyptian desert. While the physical scars are there, scientists haven't been able to extract viable Variola DNA from those specific mummies to confirm it 100%. It’s highly likely it was smallpox, but in the world of paleopathology, a scar isn't always a genetic confirmation. It could have been another poxvirus, or even a severe case of measles or chickenpox that presented strangely. However, the consensus among historians remains that the Nile Valley was one of the earliest hotbeds for the virus.
The Genetic Surprise: It’s Younger Than It Looks
Here is where it gets weird.
In 2016, researchers at McMaster University in Canada got their hands on a 17th-century Lithuanian mummy. It was a child, found in a crypt beneath the Dominican Church of the Holy Spirit in Vilnius. They managed to sequence the full genome of the smallpox virus from that child. When they compared it to 20th-century strains, they realized something shocking.
The strains were incredibly similar.
Using "molecular clock" dating—which basically measures how fast a virus mutates—the team, led by evolutionary geneticist Hendrik Poinar, suggested that all modern strains of smallpox shared a common ancestor that only dates back to somewhere between 1588 and 1645.
Wait.
If the common ancestor is that young, what happened to Ramses V?
Basically, it means that the version of smallpox that ravaged the globe in the last few centuries might be a "newer" version that outcompeted or replaced much older lineages. Or, perhaps more controversially, it suggests that the ancient Egyptian "smallpox" might have been a different, related virus that eventually died out, while the killer we know today jumped from animals to humans much later.
From Gerbils to Humans: The Zoonotic Jump
Viruses don't just appear out of thin air. They jump.
Smallpox is part of the Orthopoxvirus genus. This family includes cowpox, monkeypox (mpox), and camelpox. For a long time, the theory was that smallpox came from cows. Makes sense, right? Edward Jenner used cowpox to create the first vaccine. But the genetics don't actually back that up.
Current research points toward rodents. Specifically, African rodents like the naked sole gerbil.
It’s thought that a "pro-Variola" virus circulated in these animals for thousands of years. As humans began living in closer quarters, clearing land for crops, and domesticating animals, we created the perfect bridge. This is the zoonotic jump. At some point—maybe 3,000 years ago, maybe 6,000—the virus mutated just enough to survive in a human host.
[Image showing the phylogenetic tree of Orthopoxviruses including Variola, Camelpox, and Taterapox]
Then it learned to jump from human to human. That’s when the real trouble started. Once it became an anthroponotic disease—meaning it only lives in humans—it didn't need the gerbils anymore. It had us.
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The Vikings and the Viral Spread
We can’t talk about where did smallpox originate without talking about how it moved. If it started in Africa or the Middle East, how did it end up everywhere?
Recent studies on Viking remains have changed the map. In 2020, researchers found Variola DNA in the teeth of Viking skeletons across Northern Europe, dating back to 600–1050 CE. This was huge. It proved that smallpox was circulating in Northern Europe nearly a thousand years earlier than the "Lithuanian mummy" study suggested.
The Viking strains were different, though. They were a separate lineage that eventually went extinct. This tells us that smallpox wasn't just one single wave. It was more like a series of "spillover" events where different versions of the virus tried to take hold. Some failed. The one that eventually stuck was the one that became the global pandemic of the 18th and 19th centuries.
The Three Great Routes
Historians generally agree on three main routes that carried the virus out of its suspected origins in the Middle East or Northern Africa:
- The Silk Road: Trade is a great way to move silk, spices, and respiratory droplets. Smallpox likely hitched a ride with caravans moving toward India and China. There are Chinese records from the 4th century (specifically by Ko Hung) that describe a disease that sounds exactly like smallpox, calling it the "Hun pox."
- The Crusades: Movement of large armies is a viral superpower. When European Crusaders returned from the Middle East in the 11th and 12th centuries, they likely brought more virulent strains back to a population that had little immunity.
- The Atlantic Slave Trade: This is the darkest chapter. European colonizers brought smallpox to the Americas, where it decimated Indigenous populations who had zero previous exposure. Estimates suggest up to 90% of some populations were wiped out by "Old World" diseases, with smallpox leading the charge.
Why Does This Origin Story Matter Now?
You might think, "Why do we care where it came from if it's gone?"
Well, first, it's not "gone" in the sense that it doesn't exist. It exists in two high-security freezers—one at the CDC in Atlanta and one at the VECTOR institute in Russia. But more importantly, understanding the origins of smallpox helps us predict the next smallpox.
We are currently seeing mpox (monkeypox) move into human populations more frequently. By studying how Variola jumped from a gerbil or a camel to a human thousands of years ago, scientists can better understand the "threshold" a virus needs to cross to become a human-to-human pathogen.
Misconceptions About the Source
A lot of people think smallpox was always this ultra-deadly monster. But early on, it might have been much milder. There’s a version called Variola minor that had a death rate of about 1%, compared to the 30% death rate of Variola major.
Some researchers believe the virus actually "tuned" itself over time. If a virus kills its host too fast, it can’t spread. Smallpox found the "sweet spot"—it made you sick enough to cough and spread pustules for weeks, but kept you alive long enough to infect your entire village.
Key Facts About Smallpox Origins
- Earliest Physical Evidence: Egyptian mummies (c. 1100 BCE).
- Earliest Genetic Evidence: Viking remains (c. 600 CE).
- Likely Animal Source: Rodents, specifically African gerbils or similar small mammals.
- Most Recent Common Ancestor: Current global strains likely emerged in the 1500s.
- First Written Record: 4th-century China and 7th-century India.
Practical Takeaways for History and Science Buffs
If you're digging into this for a paper, or just because you’re a bit of a bio-history nerd, here is what you should actually pay attention to:
Don't rely on old textbooks. Any book written before 2016 will probably tell you smallpox is 10,000 years old. The new DNA evidence from the Viking and Lithuanian studies suggests a much more complex, and potentially "younger," timeline for the modern killer.
Watch the zoonotic space. The story of smallpox is a warning. Most of our worst diseases—COVID-19, HIV, Ebola, and Smallpox—all started as animal viruses. The origin of smallpox isn't just a history lesson; it's a blueprint for how spillover events happen when human habitats collide with wildlife.
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Check out the Museum of London or the Smithsonian. They often have digital exhibits on the "Great Poxes" of history. Seeing the actual tools used for early "variolation" (the precursor to vaccination) gives you a real sense of how desperate people were to stop this thing once it left its origin point.
Smallpox was the first disease we actually beat. It started as a tiny mutation in a rodent in Africa or the Middle East and grew into a global shadow. We ended it through a massive, coordinated global effort. Understanding its beginning is the best way to make sure we don't have to face a "Variola 2.0" in the future.
Next Steps for Researching Poxviruses
- Read the Poinar Study: Search for "7th Century Smallpox Genome" to see how DNA sequencing changed our understanding of the timeline.
- Investigate Variolation: Look into how 10th-century Chinese doctors used to grind up smallpox scabs and blow them up people's noses to create immunity—it’s gross, but it’s the origin of modern immunology.
- Monitor Emerging Poxes: Keep an eye on WHO reports regarding mpox to see how modern zoonotic jumps are being handled compared to the historical spread of smallpox.