Plague: illness spread FOUR TIMES faster during London's 1665 epidemic than during the 1348 outbreak

The Great Plague of 1665–6 saw disease spread some four times faster in London than it did at the peak of the Black Death in 1348, a study has concluded.

Experts from Canada analysed thousands of pages of historical records and personal documents to determine the plague picked up speed over the centuries.

The Black Death is estimated to have wiped out more than a third of the population of Europe during the 14th Century.

At this time, the count of the infected doubled around every 43 days, the team calculated — but by the 17th Century the count was doubling every 11 days.

This ‘striking acceleration’ in transmission, the researchers said, was a consequence of the increase in people living close together in cramped conditions.

The findings could help scientists to better understand how other epidemic and pandemic diseases — such as COVID-19 — spread today.

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The Great Plague of 1665–6 saw disease spread some four times faster in London than it did at the peak of the Black Death in 1348, a study has concluded. Pictured: the Great Plague

The Great Plague of 1665–6 saw disease spread some four times faster in London than it did at the peak of the Black Death in 1348, a study has concluded. Pictured: the Great Plague

The 'striking acceleration' in disease transmission, the researchers said, was a consequence of the increase in people living close together in cramped conditions. Pictured, London's East Smithfield cemetery, which was built in 1348 during the time of the Black Death

The ‘striking acceleration’ in disease transmission, the researchers said, was a consequence of the increase in people living close together in cramped conditions. Pictured, London’s East Smithfield cemetery, which was built in 1348 during the time of the Black Death

‘It is an astounding difference in how fast plague epidemics grew,’ said paper author and epidemiologist David Earn, of the McMaster University in Ontario, Canada.

In their study, Professor Earn and colleagues estimated the changing death rates by analysing data from three different sources: personal wills and testaments, parish registers, and the London Bills of Mortality.

Prior to 1538, published records of death were not available for London — so the team turned instead to mining information from individual wills and testaments to establish how the plague was spreading through the population.

‘At that time, people typically wrote wills because they were dying or they feared they might die imminently, so we hypothesised that the dates of wills would be a good proxy for the spread of fear and of death itself,’ explained Professor Earn.

‘For the 17th Century, when both wills and mortality were recorded, we compared what we can infer from each source, and we found the same growth rates.’

‘No one living in London in the 14th or 17th Century could have imagined how these records might be used hundreds of years later to understand the spread of disease.’

While previous studies — using genetic data — established the bacteria Yersinia pestis as the root cause of the plague, little had been known about how the transmission of the disease progressed.

The Great Plague of 1665–6 saw disease spread some four times faster in London than it did at the peak of the Black Death in 1348, a study has concluded. Pictured, the changing death rates

The Great Plague of 1665–6 saw disease spread some four times faster in London than it did at the peak of the Black Death in 1348, a study has concluded. Pictured, the changing death rates

Experts from Canada analyses thousands of pages of historical records (like pictured) and personal documents to determine that the plague picked up speed over the centuries

The Black Death is estimated to have wiped out more than a third of the population of Europe during the 14th Century. Pictured right: the outfit of a European Plague doctor. The beak-like mask was filled with aromatic items incorrectly thought to help ward off the disease

Experts from Canada analyses thousands of pages of historical records (like that pictured left, for example) and personal documents to determine that the plague picked up speed over the centuries. The Black Death is estimated to have wiped out more than a third of the population of Europe during the 14th Century. Pictured right: the outfit of a European Plague doctor. The beak-like mask was filled with aromatic items incorrectly thought to help ward off the disease

The findings could help scientists to better understand how other diseases — such as COVID-19 — spread today. Pictured, the Danse Macabre, inspired by the Black Death

The findings could help scientists to better understand how other diseases — such as COVID-19 — spread today. Pictured, the Danse Macabre, inspired by the Black Death

‘From genetic evidence, we have good reason to believe that the strains of bacterium responsible for plague changed very little over this time period — so this is a fascinating result,’ said paper author and anthropologist Hendrik Poinar.

Based on their estimates of the speed of the plague’s spread and information about the biology of the disease the team have concluded that the infection did not spread by pneumonic transmission — that is, human-to-human contact — in these times.

Instead, the growth rates for the early and late epidemics are more consistent with bubonic plague, which is transmitted through the bites of infected fleas.

The researchers said they believe increasing population densities, poor living conditions and cooler temperatures may explain the acceleration in the transmission rates from the 14th to the 17th Centuries.

The full findings of the study were published in the Proceedings of the National Academy of Sciences.

'From genetic evidence, we have good reason to believe that the strains of bacterium responsible for plague changed very little over this time period — so this is a fascinating result,' said paper author and anthropologist Hendrik Poinar. Pictured, the Yersinia pestis bacteria responsible for the plague

‘From genetic evidence, we have good reason to believe that the strains of bacterium responsible for plague changed very little over this time period — so this is a fascinating result,’ said paper author and anthropologist Hendrik Poinar. Pictured, the Yersinia pestis bacteria responsible for the plague

'It is an astounding difference in how fast plague epidemics grew,' said paper author and epidemiologist David Earn, of the McMaster University in Ontario, Canada. Pictured, a map showing the routes by which the Black Death spread across Europe in the 14th Century

‘It is an astounding difference in how fast plague epidemics grew,’ said paper author and epidemiologist David Earn, of the McMaster University in Ontario, Canada. Pictured, a map showing the routes by which the Black Death spread across Europe in the 14th Century

THE CAUSE BEHIND EUROPE’S BUBONIC PLAGUES

The plague, caused by the bacterium Yersinia pestis, was the cause of some of the world’s deadliest pandemics, including the Justinian Plague, the Black Death, and the major epidemics that swept through China in the late 1800s. 

The disease continues to affect populations around the world today. 

The Black Death of 1348 famously killed half of the people in London within 18 months, with bodies piled five-deep in mass graves.

When the Great Plague of 1665 hit, a fifth of people in London died, with victims shut in their homes and a red cross painted on the door with the words ‘Lord have mercy upon us’.

The pandemic spread from Europe through the 14th and 19th centuries – thought to come from fleas which fed on infected rats before biting humans and passing the bacteria to them.

But modern experts challenge the dominant view that rats caused the incurable disease.

Experts point out that rats were not that common in northern Europe, which was hit equally hard by plague as the rest of Europe, and that the plague spread faster than humans might have been exposed to their fleas. 

Most people would have had their own fleas and lice, when the plague arrived in Europe in 1346, because they bathed much less often. 

source: dailymail.co.uk