During the Middle Ages, the Black Death ravaged Europe and left nearly a third of the population dead. The epidemic reached its zenith in the years 1348 to 1350, though the disease never vanished entirely. It is widely believed that the cause of the Black Death was bubonic plague, an infectious and fatal illness spread by rodents and the fleas infesting them. Medieval people blamed the pandemic on bad air, witches, and astrology, among other things. Although most modern scientists agree that that the Black Death was caused by the bacterium Yersinia pestis, there still remain many questions about the nature of the disease and how it spread so quickly.
There has never been a definitive explanation as to why the Black Death subsided. After afflicting some seventy-five million to one hundred million people across Europe, Russia, and the Middle East, the disease began to taper off. Several factors are thought to have influenced the dramatic decline in fatalities caused by the Black Death.
Quarantine
The most popular theory of how the plague ended is through the implementation of quarantines. This entailed staying out of the path of infected individuals, rats, and fleas. The uninfected would typically remain in their homes and only leave when it was necessary. Those with the financial resources would traditionally escape to the country, far away from the Black Death-infested cities, and live in the comfort of a lavish estate. In cases where infected persons were sharing living quarters with healthy persons, the entire household was quarantined together; this may have been effective in controlling the disease in Milan, Italy, where some families were walled up in their homes and left to die.
Even religious officials did their utmost to quarantine themselves from possible infection. Because their roles required them to interact with the public, many found creative ways to fulfill the demands of their jobs while protecting their health. One bishop in Germany, for example, offered communion to his congregants via a long pole.
Hygiene
Practicing proper hygiene also likely played a role in the abatement of the Black Death. Before the pandemic struck, personal hygiene was lackluster at best. It was common to consume contaminated water. People did not wash regularly, and the dead were buried in mass graves.
During the years of the Black Death, however, people began to practice better personal hygiene. More people washed, and though bacteria had yet to be discovered, this cleanliness removed the microorganisms. People began to boil drinking water. As the bodies piled up it became more efficient to burn them, again inadvertently preventing the further spread of disease.
Clean Air
The need for clean, pure air was another important factor in ending the sweep of the Black Death. Over time, the plague became pneumonic, or airborne, passing from person to person without flea hosts. Many people sought environments in which the air quality was uncontaminated by disease. One way of inhaling pure air was to sit between two burning fires. As the bacteria were destroyed in extreme heat, this may have provided some protection. Pope Clement VI was widely known to have torches placed around him to keep infection at bay.
Many households burned incense with the aim of purifying the quality of air; some of the favored scents were beech, camphor, lemon, rosemary, and sulfur.
Handkerchiefs doused in essential oils were a popular accoutrement for many venturing outside their homes. Pressing an oil-soaked cloth to their faces, people felt safer traversing the streets. The close proximity of the handkerchief to the mouth and nose could have prevented pneumonic contagion.
Travel and Migration
As the Black Death made its destructive path across Europe, Russia, and parts of the Middle East, people began to realize the dangers of traveling or leading a nomadic lifestyle. With each new destination came the possibility of infection. Travel slowly waned, and the Black Death ran its course as would-be travelers and migrants opted instead to stay within the safety of their own homes and communities.
Other Factors
People thought that loud noises could drive the infection out of a city or village. Town officials would ring church bells at designated times or fire cannons in the hopes of forcing the plague out of the community. Healers prescribed herbal tinctures to protect the uninfected and to help those who had been stricken. Healers also employed even more nontraditional models, such as talismans or charms, to keep the plague at bay.
A factor that may have influenced the end of the plague concerned the climate. When the first widespread cases of Black Death were reported, great famines were gripping the world, especially in Europe. In general the climate was becoming colder, creating a perfect breeding ground for bacteria. A shift toward warmer temperatures could have contributed to the decline of the Black Death.
Recurrences
While the Black Death began to subside in the 1350s, it was not eliminated. Many historians believe the pandemic had simply run its course in Europe, Russia, and the Middle East, and in conjunction with improved personal hygiene and quarantines, the illness simply infected fewer people.
The Black Death was devastating to the world’s population. It would take two hundred years before Europe alone was able to replenish its population to pre-plague numbers. In addition to population losses, the world also suffered monumental setbacks in the arenas of labor, art, culture, and the economy. The pandemic did, however, contribute to the end of the feudal system.
Resurgences of the Black Death were common in medieval times. After the initial devastation, further generations endured outbreaks through the rest of the fourteenth century. Recurrences continued into the fifteenth century, though less frequently, until the threat of plague was no longer a constant shadow over daily life.
Even well after the Black Death itself came to an end, the plague still posed an occasional threat. A resurgence of the plague, often referred to as the Modern Plague, appeared in China in the 1860s and spread around the world during the second half of the nineteenth century. It is estimated that the Modern Plague led to the deaths of approximately ten million people. Additional outbreaks of plague continued to occur in the twentieth century. Between 1901 and 1909, the city of San Francisco, California, fell victim to a plague outbreak. Another outbreak occurred in Vietnam in the 1960s and 1970s while the Vietnam War (1955–1975) was in progress. Most modern instances of plague have occurred in Africa, particularly in Madagascar. Between 2010 and 2016, Madagascar was the location of half of all plague cases recorded globally. In 2015 alone, the plague was responsible for sixty-three deaths in the country.