The Unexpected Arrival of Yesinia Pestis: The Epidemiology of the Plague Outbreak at Eyam

Plague is caused by the bacterium known as Yersinia pestis. It remains one of the deadliest infectious diseases to attack humankind. There are still outbreaks in the Southern Hemisphere, in Africa, South America, the island of Madagascar and even some parts of the USA. The deadliest pandemics in recorded human history were as a result of outbreaks of plague: The Justinian Plague of 541-767, which killed 40-50% of the population and ultimately contributed to the decline of the Roman Empire; The Black Death that devastated medieval Europe, reportedly killing 25 million people, and the return of plague in the mid-nineteenth century, mainly confined to China and India. These outbreaks have been confirmed through the DNA analysis of victims’ remains as being the work of Yersinia pestis. Smaller outbreaks occurred in other centuries, including the one mainly confined to London in 1665-1666, through which the plague was brought to the quiet village of Eyam in Derbyshire.

For a great lecture series on The Black Death and the decimation of Medieval Europe, see The Great Courses series, The Black Death: The World’s Most Devastating Plague by Professor Dorsey Armstrong, available on Audible.

Plague is commonly found in rodents but it is possible for most mammals to become infected. Transfer to humans is possible when they come into contact with an infected animal and the parasites that live on them. The oriental rat flea is known to carry plague very effectively . Once infected with plague bacterium, the digestive system of the flea becomes blocked and this causes the vomiting of the bacteria into the organisms the flea then bites. Because of this, rodent-to-human transmission has been regarded the main pathway to infection. However, the research report by Lilith K. Whittles and Xavier Didelot, Epidemiological Analysis of the Eyam Plague Outbreak of 1665-1666 (2016), highlights the part that human-to-human transmission likely played in the Eyam outbreak. The modelling they used seems to suggest a quarter of infections were caused by rodent-to-human infection with the other three quarters of infections caused by human-to-human infection. This information was put to good use in the novel, Three: A Tale of Brave Women and the Eyam Plague by Jennifer Jenkins, with the initial spread outwards from the box of infected cloth into the neighbouring cottages (known now as the ‘plague cottages’ in the modern day village, each with their recognisable green signs listing victims) likely to have been the spread of the plague fleas. Following this initial period of transmission, characters begin to seemingly be infected by their fellow villagers over the course of the year. For some of our characters, kindness is what brings them into the proximity that leaves them open to infection.

Plague fleas transmitted Yersina pestis
Rats were common hosts of plague fleas carrying Yersinia pestis

As written within the narrative of the novel, the epidemic began on 7th September 1665 when a box containing damp infected cloth was hung up to dry by the tailor’s assistant, George Viccars, ultimately resulting in his death. The plague quickly spread, with five other villagers dying before the end of the month, including Emmott Syddall’s little sister, Sarah. Over 14 months the plague stalked the village, ultimately claiming 257 lives and impacting 76 families, wiping out some of them entirely. The study on the epidemiology of the Eyam outbreak suggests that infectious individuals within the same household created a much stronger force of infection compared with the rest of the village. In the novel, we encounter the plague ripping through whole families, such as was seen in the tragic total obliteration of families like the Thorpes and the Talbots and the near-decimation of other beloved families.

One of the most significant things about the plague outbreak at Eyam was the response of the villagers themselves. At the same time that plague was raging in the country’s capital and those who lived there could either flee or accept their fate due to the entrapments of poverty, the villagers of Eyam acquiesced to the imposition of a cordon sanitaire, effectively quarantining themselves for most of the year in order to keep neighbouring villages (and in particular, the lands of the Earl of Devonshire at Chatsworth) free of plague. There is some suggestion that this remarkable act of human sacrifice, which succeeded where many other contemporary equivalents had failed, may have led to a prolonging of the epidemic and the exponential increase of the death toll once the summer months hit. There is some evidence that the quarantine was broken, as can be seen throughout the novel, including the sending away of the Mompesson children to Yorkshire and the woman from Orchard Bank who tried to visit the market at Tideswell.

Whether or not the villagers also practiced ‘social distancing’ in the way in which we have done over the past 18 months during this pandemic, with the inhabitants of Eyam physically staying away from anyone not in their household, we cannot know for sure but it does seem highly likely this would have been the case and an atmosphere of caution and suspicion is somewhat probable. For our beloved characters who were drawn by necessity, or by the empathic natures of their personas, into close physical contact with those who then suffered symptoms and sickened, the power of compassion proved stronger than that of fear. The latent period of the disease, where individuals were infected but not yet symptomatic, is somewhat difficult to pin down.

Detailed analysis of historical documents, such as William Mompesson’s meticulous recording of death in the parish register at the time and the hearth tax record for Eyam in 1664, appear to suggest that initial population estimates of 350 was in reality likely much higher, with the epidemiological report by Whittles and Didelot placing the then village population at around 700. For study, they reduced this number to 689 spread over 210 households through the removal of those who died during the epidemic of non-plague-related ailments and infants born during the 1665-1666 outbreak, and their findings suggest that 257 people died of plague (37%), whilst 432 (63%) either survived or were never infected. Wealth was a factor that made survival more likely but gender had seemingly no impact.

During this pandemic we are still currently living through, we have become used to the terminology of ‘waves’ of infection. Using this modern wording (referenced in the novel in the chapter where the village is described during the spring of 1666 as being in the hollow part of a wave before it breaks; seemingly safe but actually teetering on the edge of a huge crash of more infections), the epidemic at Eyam could be described as having two distinct waves; the first in October 1665 (followed by a dying down over winter; unlike coronavirus, Yersinia pestis does not like the cold), the second beginning in June 1666 and lasting until the last death recorded on November 1st 1666 in the parish register (likely occurring on the final day of October as it is assumed bodies were buried within a day of death). During the winter months, the study suggests that rodent-to-human transmission accounted for most infections, whereas in the two peaks in October 1665 and the summer of 1666, human-to-human transmission was the apparent cause of most infections. Scientifically, this pattern is hard to verify, with the outbreak lasting only one year of seasonal cycles. In the colder winter months it may have been reduced flea activity or increased human interactivity, as people stayed warm in their own homes for the winter, that caused the decline in the number of plague victims at that time.

Infection with plague could be via rodent-to-human or human-to-human transmission routes

The epidemiological report suggests that sometimes such human-to-human transmissions occur due to the development of pneumonic plague; when plague is spread through aerosol droplets once pneumonia sets in as a result of plague infection. It is unknown whether this was the case in Eyam but some of the novel certainly borrows this theory and it may have been the case.

There are three known cases of recovery from plague recorded within the oral history of the village (no written historical records attest these) and these are documented in the novel; Margaret Blackwell, who recovers after drinking a pitcher of bacon fat; Unwin who awakens when being carried out by Marshall Howe for burial, and the gruff sexton himself, who uses his apparent immunity to profit from his grave-digging enterprise, ultimately to his own detriment.

Very sadly, there is strong evidence to suggest that the plague epidemic at Eyam disproportionately affected children, with 45.1% of plague victims in the village being under the age of 18. Hence, the harrowing parts of the novel’s narrative, where whole families of children are placed in the ground by their grief-stricken parents, is sadly true to life. It was perhaps the noticing of this by William Mompesson as he compiled the lists of the dead, that led to the decision to send the Mompesson children away to safety; something the less privileged and affluent inhabitants of the village were not at liberty to do and which caused a bitter lament from one of our protagonists. The study suggests that an infectious individual living within household was almost 100 times more likely to transmit the disease compared with an infectious person living elsewhere in the village. Proximity was key. Having an infected family member within the household greatly increased the risk of everyone living there; hence the suffering we see in the novel of whole families as the plague picks them off one by one.

Your greatest chance of survival in Eyam in 1665-1666 was to be rich and an adult.

This blog post is indebted to the research report of Lilith K. Whittles and Xavier Didelot, Epidemiological Analysis of the Eyam Plague Outbreak of 1665-1666 (2016)

Published by jenjenkins42

I am an author from a village outside of Rugby in Warwickshire. I love historical fiction. You will find me reading, hanging out with my husband, our two sons and our little dog, baking or walking.

2 thoughts on “The Unexpected Arrival of Yesinia Pestis: The Epidemiology of the Plague Outbreak at Eyam

  1. Are there any records to show when the last case of the plague in Eyam was recorded? Did infection just stop? Or was there a key factor?


    1. You can see the final death recorded on 1st Nov 1666, likely meaning the last death actually occurred on the final day of October
      There were 18 deaths in October, so it did not seem to be naturally dwindling. Personally, I think it’s a possibility the only people left had natural immunity. Many people descended from the Eyam population of that time have the Delta 52 gene, making them immune to plague and HIV. You can read about it here:


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