It was the largest pandemic in history. “The Great Plague” or “Black Death” devastated 14th century Europe. What are the symptoms of this rodent disease? Has it now completely disappeared? Insight with Annette Leclerc, epidemiologist and research director emeritus at INSERM.
What is the Black Death?
The Black Death is a plague pandemic, a disease of rodents (mainly rats, which were found in particular on merchant ships) transmitted to humans by the bites of fleas from these infected animals. Extremely contagious, the Black Death affected Europe, Asia, North Africa, and certainly sub-Saharan Africa during the Middle Ages. It is nicknamed “The Great Plague” sometimes “the black death”, “the great mortality” or even “the great pestilence”. We also speak of “the bump disease“, in reference to the “bumps” – ulcers – that she forms on the skin when she is bubonic (the most frequent form of the plague). The infection can be localized or generalized.
When did it spread?
Quoting the chapter on the plague from the book “The World History of France” edited by historian specializing in the Middle Ages Patrick Boucheron, epidemiologist Annette Leclerc recalls that the Black Death pandemic began in the middle of the 14th centuryaround the year 1347. Because populations were less on the move “the spread was slower than with Covid-19. Depending on the regions of France, the plague arrived later, by ships” explains the interviewee. “At that time, we think that it is to punish us that God sent the plague, that it is a punishment”, she continues, before recalling another medieval belief: “We thought that the disease came from the bad air, the foul smells in the streets. We continue to use the adjective “pestilential”, which means “to smell bad”” she points out. The Plague rages hard until 1352. It reappeared in France regularly, locally, but always violently, until the 18th century. In 1720, when the plague had not been detected in Marseille for 60 years, the “Peste de Marseille” ravages the city and kills in a few years between a third and half of the Marseille population, or between 30,000 and 50,000 inhabitants, according to estimates. It’s about last big episode of this epidemic in the territory. It was not until 1894 that the bacteriologist from the Pasteur Institute Alexandre Yersinthen settled in Japan, discover the bacillus (a rod-shaped bacterium) “Yersinia Pestis” responsible for this infectious disease.
How many deaths in France?
“It is difficult to answer this question, because at the time there were no precise data on mortality” rightly recalls the epidemiologist. “On the other hand, we know that the Great Plague raged more in the big cities than in the villages” she adds, and that she talked between 50,000 and 80,000 deaths in Paris. We also know that the French population has decreased by 41% in a century, between 1340 and 1440, increasing from 17 to 10 million inhabitants. The country will not regain its demographic level of the end of the 13th century until the second half of the 17th century.
How many deaths in the world?
According to some estimates, 30 to 50% of the European population of the time was decimated by the Black Death. This would have caused, on a global scale, between 75 and 200 million deaths.
What were the symptoms?
“There were actually several forms of plague: one could cause respiratory symptoms and the second, called bubonic, formed ulcers, pestilential buboes on the skin” informs the interviewed specialist. “The form could evolve according to the stage of the disease.” This bubonic plague whose incubation phase was 1 to 7 days, was the most common form of infection at the time. Located at the level of the groin or armpit, one or more) lymph node that drained the infected flea bite area increased in volume and made the patients suffer terribly, who also felt flu symptoms (high fever, body aches, etc.). This enlarged lymph node is called “bubo”, hence the qualifier “bubonic”. Sometimes this red bubo could fester and the patient healed. But in the majority of cases, the disease progressed to a pulmonary (fatal) or septicaemic form : the patient would then die within a few days of a generalized infection (sepsis). The septicaemic form could also be triggered directly – without going through the bubonic form therefore – after an inoculation of the bacillus by a cut, for example. Again, the patient would die. About the pulmonary form, it is both the rarest and the most lightning. It was transmitted from one human to another, via droplets of saliva, when the first coughed in particular. His symptoms? A violent cough with coughing up bloodseizures… Without rapid treatment, the patients lost their lives in three days.
The plague is a disease that has not completely disappeared.
Even if the epidemic has not experienced an outbreak in France and Europe for centuries, the plague is a disease that has not completely disappeared. The World Health Organization (WHO) has identified 50,000 patients between 1990 and 2015, in 26 countries. More specifically, the WHO counted between 2010 and 2015: 3248 cases of plague and 584 of them were fatal.
Is there a vaccine?
“It took centuries before there were vaccines. Until Louis Pasteur who developed a vaccine against rabies in the 14th century, vaccination did not exist” reminds the interviewee. So there was no vaccine at the time of the Black Death. The populations did not even know the origin of the disease, discovered in the 19th century only. If today several vaccines are being studied, those that have been developed so far have all been abandoned because they presented many undesirable side effects. Some were also insufficiently effective, since they did not protect against pulmonary forms of the infection.
Thanks to Annette Leclerc, epidemiologist, research director emeritus at UMS 011 of the National Institute of Health and Medical Research (INSERM).