Siege, Trade and Vomiting Fleas: The Bubonic Plague

The Black Death was a plague so potent that it killed between 75 and 200 million people (including 30-50% of the population of Europe) but Yersinia pestis also spurred medical innovation, superstition and social reform.  Let's look at:

• The Justinian Plague: The first documented bubonic plague
• The Black Death: A plague that killed hundreds of millions
• The Hong Kong Plague and Yersinia pestis: The bacterium responsible (and how it spreads)
• Bad Air, Plague Doctors and Pestilence From the Stars: Plague superstitions
• Plague Pits With Vampire Burials: Folklore's link between plague and the undead
• Quarantine and the Village That Sacrificed Itself: How a plagued village spared its neighbors

Diseased fleas rode rats to new and exciting destinations... (Simon)

The Justinian Plague

While the Black Death may be the most well known example of the bubonic plague, it wasn't the first.  The Justinian Plague raged through Byzantium during the reign of (shockingly) Emperor Justinian I.

It's thought that the outbreak began in 541AD Egypt and crossed the Mediterranean on rat infested grain ships.  The shipments of food would have been an excellent place to live for rats (and the diseased fleas they carried) as they made their way into the heart of Byzantium.

Estimates suggest that between 5000 and 10000 people dying each day in the plagued capital.  The people of Constantinople dug pits for the dead, but soon had to resort in dousing the bodies in quicklime and stashing them in towers... or floating them out to sea on burning boats.

The plague killed between a quarter and a half of Constantinople's inhabitants (the emperor himself contracted the plague but survived) and continued to cause sporadic outbursts across Europe and the Caucasus for the next two centuries.

Ships often carried rats with them... (Oleksandr)

The Black Death

The Justinian Plague was devastating, but the Black Death killed between 75 and 200 million people - including 30-50% of the population of Europe.

It's thought that the plague spread thanks to traders on the silk road and the work of the Mongol Empire.  The plague seemed to follow the Mongol army - and at the 14th century siege of Kaffa in Crimea they flung the plague-dead over the walls of the besieged city.

Kaffa was a trading city and some of the inhabitants fled by boat to Europe... carrying their infected cargo with them.  Soon the Black Death established itself across the continent, even reaching Britain.

The plague itself took three forms based on how you were infected:

• Bubonic: A flea bite infects lymph nodes, causing them to swell into "buboes"
• Pneumonic: Coughs and sneezes spread plague to the lungs
• Septicaemic: Infection in the blood, often as a result of untreated bubonic plague

Symptoms began with sweats and vomiting before moving to spasms.  Bubonic plague was the most common form - it produced bruises below the skin and swollen buboes filled with black pus.  The death toll was horrendous, especially in tightly packed areas.  Some sources claim that the population of London fell from 100,000 to 20,000 in the span of a single generation.

On a side note, did you know that the Black Death helped reform the social structure of England?  Not only did the plague seem to strike down noble, clergyman and peasant alike, the sudden scarcity of workers allowed them to negotiate better pay and rights with landowners!

It's hard to keep them out! (Svetozar Cenisev)

The Hong Kong Plague and Yersinia pestis

It wasn't until an outbreak of the plague in late 19th century Hong Kong that the bacteria responsible was revealed.  Yersinia pestis (named after researcher Alexander Yersin) was found in samples taken from plague victims and from an abundance of dead rats found in the streets.  Paul-Louis Simond identified the role of fleas in spreading the disease by placing two cages of rats (one cage infected, the other not) near each other, only for the second cage to develop the plague.

Yersinia pestis actually starves fleas by growing a biofilm in their gut.  The ravenous fleas become very aggressive feeders as a result - and each time they bite, they vomit Yersinia pestis into the wound.

Now here's the odd part - you'd think killing off rodents would be a quick way to stop the plague, but it might actually make things worse. Plague outbreaks typically happen when rodents are in short supply and fleas have to settle for much more dangerous meals - specifically, us.  Killing off rodents (even ones with plague) can result in a wave of infected fleas looking for lunch!

We also know that the Black Death was caused by Yersinia pestis thanks to the remains left in plague pits... and that the disease is till at large today.  Madagascar had a significant outbreak in 2017, with 2417 confirmed cases and 209 deaths.  You'll notice that the mortality rate is a great deal lower than that of the earlier plagues, for which you can thank modern antibiotics 

In another strange twist, people of European or Roma descent seem to have acquired a level of immunity to Yersinia pestis thanks to natural selection - a result of long term generational exposure and their ancestors surviving the Black Death!

Plague doctors relied on their costume and herbs to keep them safe... (𝕶𝖚𝖒𝖆𝖘 𝕿𝖆𝖛𝖊𝖗𝖓𝖊)

Bad Air, Plague Doctors and Pestilence From the Stars

Of course, the folk dealing with the Black Death didn't have this kind of information. One popular belief was that the plague was caused by bad air, or even smells.  

Given that sewage, refuse, fouled water and even infected wounds can all stink, it's not hard to see how someone could make a connection between bad air and illness.  To help ward off pestilential air, doctors recommended everything from wearing strongly scented herbs to firing and inhaling cannon smoke.

When plague doctors began to emerge, they didn't have a specific costume.  As medical thinking evolved, they adopted heavy (sometimes waxed)  full body outfits that probably helped a great deal against coughs or flea bites, while frequently using a wand to examine patients without needing to touch them.  The beaked masks were filled with scented herbs or mixtures to ward off pestilential air - this probably would have done little to protect them, but may have made going into areas filled with the sick and the dead more tolerable!

Funnily enough, the "miasma" theory of illness actually helped make London a healthier place.  It eventually convinced the city to invest in a sewer system to reduce the stink... which resulted in less exposure to bacterium for people in the streets!

There were other theories for the plague of course.  When the Black Death struck France in 1348, astrologers at the University of Paris informed the King that a conjunction of Saturn, Jupiter and Mars was to blame!

Folklore blamed the undead for spreading the plague... (Vitaliy Shevchenko)

Plague Pits With Vampire Burials

As if delving through the long dead bones of plague victims wasn't disturbing enough, plague pits occasionally contain "vampire burials." These skeletons have been prepared in a way intended to stop a corpse rising to feast on the dead or hunt the living

The folklore of the time suggested that the "undead" could spread pestilence to create a steady supply of corpses... which was a particularly worrying idea in the middle of a plague.  Folklore doesn't take the time to explain the weird and wonderful world of decomposition though - and a seemingly untouched corpse beneath a pile of rotten bodies would certainly breed suspicion.

Researchers in Venice found the skeleton of a female "vampire" in a mass grave, with a brick wedged firmly into her mouth.  It was thought that a new vampire would begin their career by chewing their way through their burial shroud (actually natural decay of the cloth caused by fluid and bacteria leaking from the mouth) then strengthening themselves on the dead before rising to hunt the living.  Blocking the jaws would put a crimp in that plan!

The inhabitants of Eyam in Derbyshire isolated themselves and waited to die...(Sam Barber)

Quarantine and the Village That Sacrificed Itself

Did you know that the word quarantine comes from the "quaranta giorni" or forty days, a period of mandatory isolation for land travelers to the seaport of Ragusa in 1377.  Coming by boat only held an isolation period of thirty days, but presumably the journey of the ship provided some isolation all of it's own.

Before modern medicine and antibiotics, the best defense against plague was avoiding any contact - this quarantine would offer plenty of time for the plague symptoms to appear.

That brings us to the tale of Eyam in Derbyshire, England.  In 1665, a bundle of cloth arrived from London with a cargo of infected fleas.  The infection ripped through the village, but rather than fleeing the residents agreed to enforce a quarantine on themselves to spare nearby villages.  They buried their dead outside their own houses and worshiped in the open air to minimize contact with each other while eschewing direct contact with the outside world.

The villagers still needed supplies, provided by neighboring villagers and the Earl of Devonshire. If money was to change hands, the villagers left it in the boundary stone - a boulder with six holes drilled in it, each filled with vinegar thought to kill the disease.

The plague is thought to have taken 260 out of a population of around 800, but their actions prevented the plague from escaping Eyam.

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