The medieval Plague and how science has identified the cause

Dorset,a county in the south west of England was reputedly the first part of the UK to be infected with the medieval Plague and here is the article I wrote about this for the Dorset-based Marshwood Vale Magazine:

“In this year 1348, in Melcombe, in the county of Dorset, a little before the feast of St John the Baptist, two ships, one of them from Bristol, came alongside.  One of the sailors had brought with him from Gascony the seeds of a terrible pestilence and, through him, the men of that town of Melcombe were the first in England to be infected.”  Greyfriars Chronicle


Nearly ten years ago, SARS (Severe Acute Respiratory Syndrome) emerged in the Far East sparking fears of a global pandemic.  Troubling images of men, women and children in Hong Kong and Toronto, protected by face masks were beamed around the world.  In the end the infection was controlled by traditional public health measures, but in these days of mass air travel the possibility of a quickly spreading pandemic disease stays with us.  The deadliest pandemic the world has seen actually occurred 650 years ago and Dorset has the dubious distinction of being the first part of England to be affected.  According to the report above, the disease entered the UK at Melcombe (now part of Weymouth).

The ship that docked at Melcombe in that wet summer of 1348 brought the plague and within a few days, others in the port became unwell.  Fever and flu-like symptoms would have been followed by the emergence of apple sized swellings called buboes in the groin, neck and armpits.  The buboes turned from red to dark purple or black.  Sufferers reported vomiting, headache and aching joints and up to 75% died in a few days.  This was the bubonic plague and it was accompanied by a second more deadly pneumonic form, localised to the lungs.  The infection swept mercilessly across England reaching the whole of the UK within two years and killing 30-50% of the population.  There were further waves of plague, or Black Death as it came to be called, until the 17th century.

So how did the disease spread so rapidly?  There were two culprits:  first, black rats, probably present on the ship that docked at Melcombe but happy to live on land; second, fleas that lived on the rats but also on humans.   Both the rats and the fleas carried the infection but when a flea moved to a human host it would bite and transfer the disease.   Medieval towns with their filthy conditions, cramped housing and open sewers favoured both rats and fleas and encouraged spread of the infection.   This was augmented by movement of people in their daily lives or when they fled in panic from the disease.  If they were suffering from the pneumonic form of the disease, direct person to person transmission occurred via coughing.

From the perspective of the 21st century, we tend to view plague as a historical curiosity but it still circulates and kills about 2000 people a year worldwide.  These modern cases of plague have been shown to be caused by infection with a bacterium, Yersinia pestis.  The modern form of plague seems to be much less virulent than the medieval disease so there has been speculation that another agent, perhaps the Ebola virus or the Anthrax bacterium was responsible for the medieval infection.   This speculation has been investigated in a recent study by groups from Germany and Canada using modern genetic techniques.  The researchers chose to look for evidence of the Yersinia pestis bacterium in remains of those known to have died from the medieval plague.  They went to a medieval cemetery at East Smithfield in London, known to have been used for burial of plague victims in 1348 and extracted genetic material from teeth of victims.  They found clear evidence of Yersinia pestis showing conclusively that this was the source of the 14th century disease.  If the causative agent is the same, then why was the medieval disease so much more dangerous?   It seems likely that people in the 14th century were poorly nourished with depressed immune systems and not having previously encountered the bacterium, they were easy prey.

But let’s return to 14th century Dorset to see how plague affected the way of life.   There had been rumours that a terrible illness was laying waste to Europe but, once it arrived in England, it created fear and panic on a previously unimaginable scale.  Plague respected neither class nor position; it killed indiscriminately and quickly and death was disfiguring and deeply unpleasant.  The high mortality rate disrupted normal life; crops were left to rot in fields, animals were left to roam and villages were abandoned as people fled the disease.  Portland was particularly badly affected; the quarries were deserted and coastal defences left unmanned.  Poole took 150 years to return even to its pre-plague state.  In Bridport, the number of wills recorded in the 14th century tells the terrible story.  52 wills were recorded in the entire 14th century and of these 16 were in 1348.

Unexpectedly, however, the destruction wrought by plague was a harbinger of positive social change.  It was the beginning of a gradual improvement in the way of life for peasants, previously at the bottom of the heap in a harsh feudal system.  The shortage of workers meant that peasants could now demand wages allowing them to pay rent for land they farmed.  Previously they had worked for the Lord of the Manor in return for land leased to them.   Once they were paid for work they could demand higher wages and also move where they wished.  This was the start of the breakdown of the feudal system leading to a profound and irreversible change in the way of life in this country.

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