Radio Freethinker

Vancouver's Number 1 Skeptical Podcast and Radio Show

Raising the Black Death from the Dead

Posted by Ethan Clow on October 13, 2011

Scientists have recently pieced together the DNA of one of history’s greatest killers, the Black Death. The New York Times has an article documenting the process and explaining the science behind this amazing advancement. You can read the actual science paper here.

To summarize, a group of scientists, led by Kirsten I. Bos of McMaster University in Ontario and Johannes Krause of the University of Tübingen in Germany, began to sample DNA from human remains in graveyards and cemeteries across Europe that dated back to the 14th century.

Specifically, they used DNA from teeth. Dr. Bos explains the process:

“If you actually crack open an ancient tooth you see this dark black powdery material and that’s very likely to be dried up blood and other biological tissues.

“So what I did was I opened the tooth and opened the pulp chamber and with a drill bit made one pass through and I took out only about 30 milligrams of material, a very very small amount and that’s the material I used to do the DNA work.” – source

So that’s pretty cool, they were able to reconstruct the DNA of an ancient pathogen by examining old bones and dried blood. By analyzing the DNA of the old Bubonic plague, scientist can learn a bit more about the current variation of it. Obviously bacteria will evolve over time like all living things but it turns out that this particular bacteria is a slow evolver. Of the bacterium’s chromosome, which is about 4.6 million DNA units long, only 97 of these DNA units have changed and only a dozen of these changes occur in genes and therefore would affect the organism’s physical properties.

The goal is to create a living version of the ancient Bubonic plague. Wait, what?

“Such a microbe could be handled only in special secure facilities. But even if it did infect a person, the bacterium would be susceptible to antibiotics, like its living descendants, said Hendrik Poinar of McMaster University, a team member.” – source

So aside from the troubling question of why these scientists are playing Frankenstein with the Black Death, this is pretty cool research. Here’s another question arises, if the ancient bacterium is so closely related to the current strain, why does the current strain seem to be far less deadly? What does “less deadly” mean? Apparently the modern plague has a mortality rate of 1-15% in treated cases and a 40-60% mortality rate in untreated cases.  Additionally from 1987-2001,the World Health Organization has reported an annual average of 38,876 cases of the plague with 2847 deaths worldwide.

Granted, that’s not the most reassuring numbers but when you compare the way the plague cut through the population of Europe, it was like a hot knife through butter.

How to explain this discrepancy? What we need is some Historic Context!!

When the Black Death hit Europe in the 1300’s things weren’t going well for the average European. The average person was extremely malnourished. Food was scarce and what little food you got wasn’t particularly healthy for you. Major famine had repeatedly struck western Europe at this time, which was only exasperated by the climate getting colder (the Little Ice Age)

Economically, Europe was in trouble (sound familiar?) there is evidence that the average person was basically scrapped for cash and having trouble making ends meet. People couldn’t buy enough food or live in great conditions. And then to make matters worse, a giant war broke out. The Hundred Years’ War (although it didn’t last 100 years) between England and France broke out in 1337 and left the countryside of Europe decimated.

It was a perfect storm for an invading microbe. When the Black Death hit, people thought it was the end of the world. It almost was. People would get infected and if they didn’t die within hours, would be dead in a few days. Since the disease (pasteurella pestis) was spread by fleas who liked to hang out on rats, the unsanitary conditions of medieval Europe were like a smorgasbord for the bacteria.

It’s estimated that the Black Death killed off about 30 – 60% of Europe’s population. The disease spread fast as well. It entered Europe in 1347 and by 1352 it had spread all across the continent and into Russia.

If for some reason you ever travel back in time to this period and want to escape the plague, head to central Europe, somewhere between Prague, Cracow and Warsaw, for some reason, we aren’t too sure why, the plague didn’t really spread there and those areas remained largely uninfected.

Getting back to the science of the Black Death, this research also solves a few debates over the origins of the plague. The majority of scientists accept the theory that the plague was caused by pasteurella pestis however, some have maintained that could not be the case. Other theories suggesting the culprit was an Ebola-like virus or perhaps something related to Anthrax. For many of these theories, the evidence often comes up that the description of symptoms doesn’t match what Bubonic plague does. I’m skeptical of such claims for a few reasons.

A) Medical science wasn’t very good back then. Doctors, if you want to call them that, for the most part stood around and when “duuuhhhhh” at the mountain of bodies that piled up during the plague. So I’m not surprised that descriptions of symptoms are spotty or appear inconsistent.

Duuuhhhhhh

B) People weren’t really aware of disease as communicable in our sense of the word. Sure they would isolate people who had the illness but they didn’t get the idea of washing your hands or not living in squalor. The treatments they did have, like bloodletting were just making things worse. So again, people might also be dying from treatment, let alone the Black Death.

But this new research really points to pasteurella pestis being the culprit here. DNA doesn’t lie and this is really a slam dunk in that department. Especially if they are able to take the DNA code and make a living sample of the ancient plague.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s