What do we think of when we hear the word “plague”? Red crosses on boarded-up doors? Deserted medieval villages? Or maybe the horror film-esque cloak and mask of a plague doctor?
Unsurprisingly, the history of plague and its impact on health regulation is more complex and far-reaching than many assume. This extract from the Textbook of Global Health looks at the medical and environmental legacy of pandemics, which range from the Plague of Justinian, to the infamous Black Death and beyond.
For the most part, scientific ideas, technologies, and practices in medieval Europe trailed those of other societies, particularly in the Islamic world, where influential advances were made in such areas as astronomy, surgery, theories of disease-transmission, mind-body connections, and medical institutions. European healing involved a combination of local wisdom (e.g., knowledge of medicinal herbs passed down from generation to generation and among lay practitioners, including midwives who apprenticed with other wise women) and a hierarchy of town-based practitioners, such as apothecaries, barber-surgeons, and university-trained physicians.
It was during the Middle Ages that hospitals and religious orders dedicated to healing were established in Europe, partly to care for crusaders returning from Church-sanctioned military campaigns to recapture Palestine from Muslim control. Some institutions, such as St. Bartholomew’s in London, founded in 1123, still function today, as does Santa Maria Nuova in Florence. From about the 13th century on, secular hospitals were also founded in many larger European cities, though there was continued importance of the complementary role of the healing of the body and the healing of the soul.
Other changes were afoot that would test sanitary localism and Europe’s backwardness. As rival leaders fought for land and power (needing ever greater resources for these exploits), and merchants became interested in the riches and resources of faraway places, travel and commerce gradually increased, with microbes as companions. The congested towns of late medieval Europe were typified by poor sanitation and hygiene in comparison to some contemporary civilizations elsewhere, such as the Aztec Empire, and thus became loci of epidemic disease.
Plague is among the earliest documented pandemics, with two great outbreaks bracketing the Middle Ages. The first, known as the Plague of Justinian, struck in 542 CE, decimating populations throughout Eurasia. The second pandemic began with the Black Death in 1347 and lasted until the late 17th century. It was the most destructive epidemic in the history of humankind, which resulted in an estimated 100 million deaths (almost one quarter of the world’s population, especially striking Asia, Europe, and the Middle East).
Surmised to have originated in wild rodents (probably in Central Asia), whose habitats were disrupted by a mix of human invasion, expansion of farming lands, and new trading patterns, what became known as the Black Death traveled by land and water along the Silk Road. It reached the Black Sea in 1346. By 1348 it had spread northward to Russia, westward to Europe, eastward toward China, and south-westward to the Middle East.
Although its cause was unknown, plague’s suspected communicability led to the earliest attempts at international disease control. In 1348, believing that plague was introduced via ships, the city-state of Venice adopted a 40-day detention period for entering vessels (a policy soon copied by Genoa, Marseille, and other major ports) after which the disease was believed to remit. This practice of quarantine—from the Italian word for forty—was minimally effective in stopping plague. Quarantine’s stricter counterpart, the cordon sanitaire—a protective geographic belt barring exit of people or goods from cities or entire regions—would also be used frequently in succeeding centuries. In 1423 Venice established the first lazaretto, a quarantine station to hold and disinfect humans and cargo. Its island location was emulated by other cities across the world.
Because the Black Death’s initial appearance preceded the formation of nation-states, sanitary efforts in the 14th century were adopted and implemented by municipal authorities with little coordination. While word of disease spread through travelers, initially there was no official system of notification or cooperation between city-states. However, by the 15th century many Italian towns and cities established plague boards, sometimes made into permanent public health boards, charged with imposing the necessary measures at times of outbreak. This precursor to international health authority, though local, rapidly developed a cooperative dimension through frequent correspondence between the plague boards.
Over time, new ideas evolved around plague’s communicability, justifying ever-stricter quarantine measures. In 1546, the Veronese physician-scholar Girolamo Fracastoro revived ancient notions of contagion in his tract on plague transmission, theorizing that “seeds of disease” could be spread either through direct contact or by dissemination into the atmosphere.
Though the virulence of plague lessened somewhat in the 15th century, subsequent visitations worsened. In 1630–1631, plague killed one quarter of the population in Bologna, one third in Venice, almost half in Milan, and almost two-thirds in Verona. A scant generation later, half of the inhabitants of Rome, Naples, and Genoa succumbed to the plague of 1656–1657.
Plague, of course, was not the only deadly or epidemic ailment of the Middle Ages and early modern period. Smallpox, diphtheria, measles, influenza, tuberculosis, scabies, erysipelas, anthrax, trachoma, leprosy, and nutritional deficiencies were also rife. Less familiar today, mass hysteria in a climate of superstition led to outbreaks of dancing mania (St. Vitus Dance). Ergotism, arising from fungal contamination of rye, killed or disabled large numbers of people in dozens of epidemics between the 9th and 15th centuries.
Spurred on by more stringent sanitary enforcement during plague years, concepts of cleanliness and sanitation gradually took hold in Europe’s cities. Through increasingly forceful legislation and public awareness, announced via the printing press (c. 1440) and town criers, urban centers began to approach the hygienic standards reached by the Roman Empire more than a millennium earlier. Influenced by neo-Hippocratic ideas on the link between health and ‘airs, waters and places,’ health boards and many local governments took on more rigorous control of street cleaning, disposal of dead bodies and carcasses, public baths, and water maintenance. By the 18th century, cities began to employ, fitfully, a new environmental engineering approach to epidemic disease, which emphasized preventive actions including improved ventilation, drainage of stagnant water, street cleaning, reinternment, cleaner wells, fumigation, and the burial of garbage.
Even before the plague fully retreated, a new economic system began to develop that would irrevocably shape worldwide patterns of disease and eventually lead to international health measures and institutions.
Featured image credit: A street during the plague in London with a death cart and mourners by Edmund Evans. CC-BY-4.0 via Wellcome Collection.