The Black Death killed around one-third or about 25 million people in Europe during the 1300s.
This is a staggering number, which is why the Bubonic Plague was once the most feared
disease in the world. The crazy thing is that the bubonic plague is still around today.
Approximately seven people are infected with the Black Death every year in the United States.
And it gets worse; people in parts of the world without access to medical supplies
are getting sick and dying from the bacteria that causes the bubonic plague as you watch this video.
But where did the Black Death actually come from?
This is a mystery that scientists have been trying to solve for centuries.
Now an interdisciplinary team of researchers from the Max Planck Institute in Germany
has tracked down what is likely the origin of the Black Death, and their conclusion might shock you.
The bubonic plague is caused by a bacteria called Yersinia
pestis. It’s a nasty microbe that most often gets into a body via a flea bite
and immediately seeks out the lymph nodes where it wreaks all types of havoc. Originally,
people thought the bubonic plague was caused by rodents such as rats, but it wasn’t the rodents
themselves that infected people. It was the fleas that hid within their hair who were to blame.
When a flea carrying the Yersinia pestis bacteria bites a human,
the bacteria gets into the bloodstream, where it’s carried throughout the body.
The bacteria has a defense mechanism that allows it to fight off white blood cells
so that it can continue on to a lymph node without being destroyed. It’s here that the bacteria
begins to reproduce. The incubation period the disease is somewhere between 2 to 8 days,
at which point the bacteria have multiplied to dangerous levels, and the body’s lymph
nodes begin to swell into painful buboes. This is where the bubonic plague derives its name from.
The lymph nodes swell as a result of the bacteria multiplying uncontrollably
and hijacking the body for their own purposes. The infection begins to spread throughout the body,
which results in the host becoming incredibly sick. The immune system tries desperately to
control the infection, but since the lymph nodes have been compromised, it overreacts.
This is actually the main cause of death associated with the bubonic plague.
As the bacteria spreads from the lymph nodes into the bloodstream
and around to the rest of the body, the immune system kicks into high gear,
and the body goes into septic shock. The blood vessels begin leaking fluids,
which decreases blood pressure and the amount of nutrients carried to vital parts of the body.
Abdominal clotting can develop while main organs begin to fail, which eventually leads to death.
The most horrendous part of the Black Death is what happens to the body itself.
The lymph nodes swell to incredible sizes. This occurs most often in the armpits, groin, and neck.
Normally they become around the size of a chicken egg as the infected nodes push against the skin.
While the lymph nodes swell, the infected person develops a high-grade fever
as the immune system desperately tries to do everything it can to kill the bacteria.
This nasty disease killed millions of people during the 1300s
when the plague began and continues to do so even in the present. So,
where did it come from, and how did the Black Death reach Europe, the Middle East,
and North Africa, where it decimated the populations of these regions of the world?
Until recently, most researchers believed that the bubonic plague
originated in China or East Asia. It was thought to have been brought to the west via the Silk Road
and trade routes across the continent. However, researchers recently discovered
that the bacteria actually originated in Central Asia in what is now Kyrgyzstan.
The team now believes they have pinpointed the origin of the bacteria that started the
bubonic plague not just to the country but to a specific set of villages. Using archaeological,
biological, and chemical evidence scientists were able to trace the plague-causing bacteria
back to Lake Issyk Kul, located in the northeastern part of Kyrgyzstan.
The first clue that led researchers to this discovery was that archaeological evidence from
the sites of Kara-Djigach and Burana, which are located in the Lake Issyk Kul region,
indicated that an epidemic swept through the local trading community sometime between 1338
and 1339. Based on the analysis of tombstones found in the area,
several of these grave markers stated that the cause of death was “pestilence” or disease.
The fact that so many in the area died of an unknown disease right before the
bubonic plague pandemic in Europe was a good indicator that the Lake Issyk Kul region
might have been the origin of the Black Death. Most scholars believe that the plague in Europe
began to take off around 1347. The researchers from the Max Plank Institute explain that the time
between the outbreak in Kyrgyzstan and the Black Death in Europe can be accounted for due to the
fact that the disease had to evolve into multiple different strains before the pandemic could begin.
The bacteria also needed to find a way across the Asian content to Europe and North Africa.
It most likely found this path aboard stowaway rats on trade ships and caravans. One of the
most deadly plagues the world has ever seen might have started with a single flea on a single rat
traveling west from Kyrgyzstan. Once the rats with infected fleas made it to the Mediterranean, they
likely spread their fleas to other rodents, which then carried the infection to the rest of Europe.
But this was all just circumstantial evidence and guesswork. The researchers needed more evidence
to support their theory. Luckily, they found it in the bones of long-dead villagers from
the Kara-Djigach and Burana sites in the Lake Issyk Kul region. After the skeletal remains
of people at the sites were carefully dug up, they were sent to the lab for further analysis.
When biologists sequenced the DNA of each individual, they found something surprising.
Human DNA was not the only genetic information stored in the bones.
As the sequencing came back, scientists found there were remnants of bacterial DNA as well.
The researchers had a hunch that Yersinia pestis might have been
responsible for the deaths of the seven individuals they analyzed at the lab,
but they couldn’t be 100% sure. Then they found the smoking gun, or at least part of it.
The bacterial DNA was fragmented. It might have belonged to an early form of Yersinia pestis,
but there just wasn’t enough information to come to a definitive conclusion. Then the scientists
caught a break. As they continued to analyze the bones recovered from the archaeological site,
they came across a second bacterial DNA fragment. It had some of the same
sequences as the first strand they found but also contained fragments they were missing.
The geneticists analyzed the strands together and compared
them to Yersinia pestis. The results were shocking.
When the two bacterial strands were sequenced, scientists found that they belonged to the
same type of bacteria. The DNA indicated that the bacteria present was a common ancestor to
the strains of Yersinia pestis that eventually evolved and proliferated during the time of the
Black Death. This new evidence solidified the theory that the Black Death didn’t
originate in the far East but right there in the Lake Issyk Kul region of Kyrgyzstan.
The puzzle pieces were falling together. This was the earliest genetic, archaeological,
and historical evidence of the bubonic plague ever found.
Researchers knew that the dates and cause of death on the tombstones were not enough
evidence to definitively prove their theory. But by combining the inscriptions, artifacts,
and genetic information recovered from the sites, they could confidently say that the initial strain
of Yersinia pestis that later would become the bubonic plague originated in Kyrgyzstan.
The researchers made it clear in their final paper that the Lake Issyk Kul region was not
where the pandemic itself started but where the bacteria evolved. The strain of Yersinia pestis
in Kyrgyzstan is the earliest ever found that can be directly traced to all of the
different variants that arose during the bubonic plague pandemic of the 1300s.
The exact strain that evolved in the Lake Issyk Kul region was not the one that swept through
Europe. However, it was most certainly deadly, as was evident by the trail of bodies it left behind
at the archaeological sites of Kara-Djigach and Burana. Without this strain of Yersinia pestis
evolving in the early 1300s, the bubonic plague would likely never have spread throughout Europe,
the Middle East, and North Africa. It was the bacteria from Kyrgyzstan that
had the ability to hide within fleas and evolve as it was carried across the world.
When the bacteria found its way to the more densely populated regions of Europe,
it thrived. Like with all pathogens, every time it found a new host and started reproducing,
there was a chance it would evolve into something stronger and more deadly. This
is exactly what happened. The different strains of Yersinia pestis were able to infect huge numbers
of hosts who then carried the illness with them across trade routes and back to their families.
Once Yersinia pestis got into the cities and densely packed trading ports of the
Mediterranean, there was no stopping it. The bubonic plague spread like wildfire,
and since there was no modern medicine in the
1300s and no one had any idea what caused the disease, millions of people perished.
Today we have antibiotics that can kill Yersinia pestis and cure anyone who is infected by the
bubonic plague. However, not all parts of the world have access to these medications,
which means people are still dying from the Black Death even today.
Now watch “How Did Bubonic Plague (Black Death) Actually End?”
Or check out “How the plague doctor's mask protected them.”