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From Leprosy To COVID-19: The Evolution Of Quarantines (Part 1)

By: Deanna Altomara

The current quarantines and travel restrictions taking place across the world represent the largest quarantine in human history. People have dealt with pandemics—the global spread of a specific disease—for centuries. 

Infectious diseases are caused by microorganisms that spread from one person to another. But the way that disease is spread varies by the type of microorganism at work. Some diseases are transmitted through blood, insect bites, certain forms of sexual contact, or other mechanisms. While there is still a lot to learn about the current COVID-19 virus, it appears to be primarily spread through airborne droplets released when an infected person coughs or sneezes, or through the close contact (about six feet or less) of an infected and uninfected person. At the moment, it appears that patients are most contagious after they have developed symptoms, although it may be possible for the disease to spread before a person develops symptoms. However, the situation is rapidly changing and scientists are still learning about the transmissibility of this disease. 

Throughout history, person-to-person contact has facilitated the spread of infectious diseases. Diseases have historically followed trade routes, carried by unsuspecting travelers and merchants. While ancient peoples didn’t understand how diseases spread (although they had their theories, including “bad air” and the wrath of the divine), they saw how refugees from outbreaks seemed to carry the disease with them. This observation led to the first rudimentary tools of quarantine and isolation. As people barricaded themselves against possibly-infected foreigners, fear and stigmatization of strangers took ingrained itself in the public consciousness. 

As international trade networks have strengthened, the risk of a pandemic has loomed more and more likely. Over the last decade, the world has become more connected than ever before. This three-part article will explore the evolution of quarantine to the measures that we are seeing today with COVID-19. 

This depiction of leprosy appears in a fifteenth-century manuscript.

One of the earliest references to quarantine appears in the Old Testament, where the Book of Leviticus instructs Hebrews on how to quarantine victims of leprosy. Once identified, the lepers were sent to live outside of town and their clothing was burned. Lepers were considered ritually unclean by the Hebrews, a belief that led to widespread stigma throughout the Middle Ages and into today’s world. [1]

In the sixth century CE, the bubonic plague swept the Byzantine Empire with a 40% mortality rate, killing up to 25 million people.[2] To cope with the influx of corpses, the famous Emperor Justinian hired boats to dump bodies into the Mediterranean Sea. He blamed Jews, Samaritans, pagans, heretics, Arians, and homosexuals for infecting innocent Christians, and passed laws restricting their movements.[3] Ultimately, this plague hastened the fall of the last standing arm of the Roman Empire.

Medieval Plague Doctors wore bird-shaped masks to protect themselves from inhaling the disease.
I. Columbina, ad vivum delineavit. Paulus Fürst Excud〈i〉t.

The Plague of Justinian was a precursor to the infamous Black Death, which killed up to 50 million people in the fourteenth century.[4] The plague was caused by a bacteria called Yersinia pestis, which lives in flea-infested rodents. The plague spread through Central Asia before traveling on trade ships to the Mediterranean, where it began its decimation of Europe, killing an estimated two-thirds of the continent. As a major trade hub, Venice was one of the first cities to crumble. In 1423, the port city built the first maritime quarantine station on a small island, called a lazaretto after the biblical leper Lazarus.[5] Upon arriving in Venice, ship captains were asked to provide paperwork confirming the health of passengers and crew. If the results were unsatisfactory, the ship, its people, and its contents were isolated on the lazaretto for thirty days. This time period was later extended to forty days, the length of time that Jesus spent in the desert. During this time, Venetians believed the miasma, or infected air causing the illness, would evaporate.[5] Today, the word quarantine comes from the Italian quarantinario, the forty-day isolation period. Meanwhile, the word isolate is related to the Latin insula, or island, where the infected were quarantined.     

Boccaccio’s ‘The plague of Florence in 1348’. Etching by L. Sabatelli.

Not long after, the plague reached the northern Italian countryside. Victims were quarantined in their homes and guarded so that they couldn’t leave. According to one source,

“where cases of the plague were first discovered, all the occupants of the three houses concerned, dead or alive, sick or well, were walled up inside and left to perish.” [3]

Meanwhile, the Duke of Milan passed an edict that all victims must be sent to a field or forest until they recover or die. Later, a nearby town established a quarantine station where “purification by sun and wind” could take place. Fresh air was considered to have healing properties, and many quarantine stations were separated from the rest of society by a flowing river or other natural barrier. Meanwhile, another common medieval method of disease control was the “cordon sanitaire,” or sanitary barrier. This barrier marked an official boundary which nobody was allowed to cross.[5] As a part of this strategy, hidden observation posts were placed at strategic points along the Italian coastline. Armed guards prevented illegal ship landings, and quarantined any people who did make it through the sanitary cordon. These crude measures produced a limited amount of success in containing the plague.[4]

An image from a fifteenth-century copy of the Decameron, which describes the plague in Florence

These long-ago plagues might seem distant in comparison to the COVID-19 pandemic currently spreading around the world, but they played an important role in the development of more modern methods of disease control. Check back in tomorrow to see how these modern quarantine techniques evolved.

Editor’s Note: If you’d like to share your COVID-19 or quarantine story, please fill out the contact form on this post.


[1] Bennett, B. H., Parker, D. L., & Robson, M. (2008). Leprosy: steps along the journey of eradication. Public health reports (Washington, D.C. : 1974), 123(2), 198–205. 

[2] Wagner, D., Klunk, J., Harbeck, M., Devault, A., et al. (2014). Yersinia pestis and the Plague of Justinian 541-543 AD: a genomic analysis. The Lancet, 14(4), 319–326. doi: 10.3410/f.718258232.793493962

[3] Drews, K., 2013. A Brief History of Quarantine. The Virginia Tech Undergraduate Historical Review, 2. DOI: 

[4] Alfani, G., & Murphy, T. (2017). Plague and Lethal Epidemics in the Pre-Industrial World. The Journal of Economic History, 77(1), 314-343. doi:10.1017/S0022050717000092 

[5] Tognotti E. (2013). Lessons from the history of quarantine, from plague to influenza A. Emerging infectious diseases, 19(2), 254–259.