Guess what?
It may have occurred nearly 700 years ago, but scientists have discovered that the long-term
effects of the Black Death are so profound that this medieval plague is still impacting
us even today.
Stay tuned to this week’s video from History Calling to find out what they learned when
they dug up and analysed hundreds of plague victims and how the Black Death affects you.
There has been some dispute as to exactly where the Black Death originated.
Some think it was in China, others that it emerged in what is now northern Kyrgyzstan.
When it emerged is also up for debate.
1346 is the most widely agreed upon year, but in 2022 an article released in the Nature
journal contained fresh research carried out on seven skeletons discovered in Kyrgyzstan
in the 19th century and since stored in Russia.
Tombstones showed that some of these skeletons were buried in the years 1338 and 1339 and
some recorded that the dead had expired from ‘pestilence’.
After DNA analysis, it was established that three had died from the illness now called
the Black Death.
If these individuals were indeed ground zero for the sickness, then that pushes its start
date back an extra eight years.
Wherever and whenever it began though, it didn’t stay there.
By the mid 1350s it had spread through Asia, Europe and North Africa, producing one of
the most devasting natural selection events in human history.
Given the lack of historical records created and kept from this time, it’s impossible
to say with much accuracy how many people the Black Death killed, but depending on which
estimate you read, it wiped out 30-60% of those it infected, massively reducing the
human population by anything up to about 50 million people.
Remote areas with low population densities like Finland and Iceland were largely spared,
but they were the exception.
For most people, there was nowhere to hide.
All they could do was watch in horror as hundreds and then thousands of people died around them,
burying the bodies, praying for mercy and waiting to fall ill in their turn.
One Florentine chronicler wrote that the corpses were buried in mass graves, layered on top
of one another with a thin layer of earth in between ‘just as one makes lasagne with
layers of pasta and cheese.’
It’s little wonder that this pestilence is often called the deadliest plague in our
history.
It is caused by the yersinia pestis bacterium, so named because one of the French scientists
who discovered and classified it was surnamed Yersin.
This bacterium started with rats and infected the fleas living on their bodies.
When their rodent hosts died, the fleas moved to humans instead.
The land and sea trading routes in use at the time allowed the pestilence to spread
through the three connected continents and by the time people realised what was happening,
it was too late.
The cat (or should that be the rat) was out of the bag and humanity had a catastrophic
pandemic on its hands.
The symptoms could be excruciatingly painful.
The Black Death is referred to as bubonic plague because it causes buboes to appear
on the body when lymph nodes became infected with the plague bacterium and swell up, just
as you see on this 20th century victim (and yes, before you ask, it is indeed still possible
to be infected with yersinia pestis today, but fortunately treatment options are much
better).
A fever was also common as were black spots on the skin, bad headaches and nausea.
Some argue that it was these black spots which led to the name Black Death however this is
contested.
Historian Ole J. Benedictow (and I’ll leave his book and an article he wrote linked below),
says that in fact the name probably stems from ‘a mistranslation of the Latin expression
atra mors, in which atra may mean both terrible and black.
It has nothing to do with clinical symptoms or features, as persons seeking a rational
explanation for this graphic term often believe.’
The common use of the name also long postdates the pandemic it describes.
Benedictow tells us that other than one isolated case in the account of a doctor named Simon
of Couvin (which is a town in Belgium), the term Black Death was not used during the fourteenth
century and only gained traction in the seventeenth.
Whatever its name, it was a terrifying illness.
From the onset of symptoms to death typically only took a few days.
Unlike other plagues the victims of the Black Death who succumbed to the disease were not
mainly from amongst the elderly.
Your chance of dying did increase if you were in an older age cohort, but it also decimated
a huge portion of the breeding-age section of humanity as well.
Nor did it spare the wealthy, despite their access to better diets and housing and easier
lifestyles which might have made them healthier and more resilient to serious illness.
Princess Joan of England, the 14-year-old daughter of Edward III, was one notable victim
for instance.
Whilst travelling to Castile in 1345 to be married to Prince Pedro, son and heir of Alfonso
XI, the girl contracted the Black Death and died in the village of Loremo in France.
Her would-be father-in-law was another victim, dying at Gibraltar in 1350 at the age of 38.
The fact that the disease relied on rats and fleas so much meant that outbreaks typically
subsided during the winter months, when these creatures and insects would decrease in number
and Benedictow has convincingly shown that the Black Death did comparatively little of
its spreading via human coughs and sneezes (a type of infection known as pneumonic plague).
He says that:
The bloodstream of humans is not invaded by plague bacteria from the buboes, or people
die with so few bacteria in the blood that bloodsucking human parasites become insufficiently
infected to become infective and spread the disease: the blood of plague-infected rats
contains 500-1,000 times more bacteria per unit of measurement than the blood of plague-infected
humans.
Had the plague been spread in large part by human-to-human transmission via droplets in
the air, it would have continued to prosper in the winter as well.
That said, Benedictow notes in his book that those who were infected with pneumonic plague
almost invariably died.
This outbreak of plague petered out in the 1350s, though there continued to be sporadic
eruptions of it across the three continents for centuries to come.
If you want more information on these, see my video on how it affected the English village
of Eyam, in the mid-1660s, where you can hear about the heroic measures the villagers took
to try to contain it and the terrible price they paid.
[victim] It has been centuries since the world suffered massive bubonic plague events of
the type seen in the 1340s and 1350s, or even the 1660s though, so how is it that we are
still experiencing the after-effects of this illness en masse today?
How does the Black Death affect you?
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The answer to the question of how the Black Death still affects us today was published
by a team of scientists in October 2022, also in the journal Nature, though this is a different
article to the one I discussed a few minutes ago.
I’ll leave both linked below, though I should warn you that they’re a tough read for anyone
like myself who doesn’t come from a science background.
The scientists behind the October article studied the exhumed skeletons of 516 individuals
from England and Denmark and, using things like carbon dating and historical records,
grouped them into cohorts who lived before the Black Death and after.
Some were even exhumed from the famous plague cemetery of East Smithfield in London and
their deaths could be dated to during the pandemic itself.
Of these 516 they found they had 360 whose bones produced sufficient DNA for analysis.
They then tested said remains and obtained some fascinating results.
Historians and the world of medicine had long wondered why the Black Death killed some people
and not others and the answer seems to lie in the genes they inherited from their parents.
The team examining the DNA were looking for certain alleles that were found more frequently
in the remains of people who lived after the Black Death (which would suggest that those
alleles offered protection from the disease and that’s why they were more prevalent
after it had hit England and Denmark).
They were also looking for alleles which were more prevalent only in those people who lived
before the pestilence, which would indicate the opposite; that these alleles made one
more susceptible to the illness and so decreased in frequency after the plague because those
who carried them were more likely to die and be unable to pass on their genes to future
generations.
They found what they were looking for.
Certain infection-fighting genes were indeed more common in the bones of those generations
immediately following the Black Death than those who lived before it.
Furthermore, the difference was so stark and had happened so quickly that it couldn’t
be accounted for by any other evolutionary process.
It had to be the impact of the disease.
This fitted with other observations about the plague more generally.
The scientists had already suggested that the continued outbreaks of plague over the
following centuries, which gradually killed fewer people for the most part, could be accounted
for in part by ‘human genetic adaptation to Y.
Pestis’ and this is exactly what their research found.
People who were naturally more likely to survive the plague did, then passed on their tougher
genes to the next generation.
Over the course of hundreds of years this made it harder and harder for the bubonic
plague to wipe out huge numbers of the human population.
Now you might be thinking this all seems great.
Those of us alive today with European, Asian and North African heritage are pre-programmed
to be more immune to this type of plague because we’re descended from those people who proved
able to survive it and that’s what History Calling meant when she said that the Black
Death is still affecting us today.
But there’s more to come and the next revelation is far less positive.
The scientists also discovered that the very genes which are offering us some protection
from bubonic plague also have another, far less friendly effect.
They make us more susceptible to auto-immune diseases such as Crohn’s and lupus.
Now for those of you who are, for example, native Americans with no European, Asian or
North African ancestry, this is no big deal.
You can now sit back and enjoy a smug smile as you won’t be affected by the long-term
problems associated with this particular plague.
However in this day and age I’d say that there are very few people who don’t have
any ancestors post-1346 from anywhere in the affected areas, so I think this is a bit of
a bummer for the vast majority of us.
It does go to show one of my personal maxims however, which is that no matter what some
people obsessed only with the here and now may claim, whether we like it or not, history
matters.
And on that note my friends, that brings us to the end of another video.
Let me know in the comments below what you think the worst part of being alive during
the Black Death outbreak would have been; watching others die, burying the bodies, waiting
for your own infection or something else.
If you’d like to know more about plague history try one of these options next.
Whatever you choose, please enjoy and until then, keep learning.