Monday, 16 March 2020

Coronavirus, Quarantine, and Contagion: A Historical Perspective

The spread of Covid-19, or coronavirus, has led many countries and localities to resort to quarantine as a mechanism to contain this new disease. Medical isolation, as quarantine is often called today, has a long history, and its use owes little to modern medical science. 

Examples of isolation of the sick can be found in the Bible, in the Islamic World from the 7th century, and in medieval Europe. Interestingly, most of the quarantine measures currently being used to contain or delay the spread of coronavirus have been used for centuries or longer.

The practice of isolating people with diseases in the past, as today, was based on the belief that the sick were contagious: that they could infect the healthy. That was correct for some diseases, but not others. Even among those that were contagious, some were much less contagious than others. For this reason, contagion theory was controversial until the role of microbes in many diseases was firmly established in the late 19th century. Before then, contagionists could seldom demonstrate how diseases could be transmitted from person to person (or animal to animal).

Diseases transmitted by mosquitoes, like yellow fever, or by contaminated water, like cholera, complicated things for contagion theory. Opponents of contagionism pointed out that people in close contact with the ill often remained healthy, while people who had no such contact contracted yellow fever or cholera.

Contagionism's main competitor until the establishment of germ theory was the miasmatic theory. Miasmatists believed that most diseases were conveyed in the air, through miasmas, or "bad air" ("mal aria" in Italian). Marshes and swamps were considered to be major sources of miasmas, as was rotting organic matter, including human and animal wastes. In the late 18th and 19th centuries, the miasma theory gained many adherents, partly because the growing, unsanitary, and often polluted urban areas produced powerful, obnoxious odors. The miasma theory was wrong but it often led to draining of marshes and the implementation of sanitary reforms that reduced disease mortality.

In the 19th century, however, many traders used miasma theory to oppose quarantine, which could literally shut down ports for weeks or months. They argued that the source of the disease was not incoming ships or people, but miasmas generated locally by unsanitary conditions. 

As is the case today, a concern for health competed with a concern for the economy. As Benjamin Strobel, a Charleston, South Carolina doctor, wrote in 1840: "Truth and justice have been too often sacrificed to expediency and policy, and never more so than in reference to yellow fever. Has it not occurred, when the disease actually invaded us, that there were men who, regardless of the lives of others, and listening only to the sordid suggestions of avarice, have endeavored to conceal the fact?" (Benjamin B. Strobel, An Essay on the Subject of Yellow Fever, Intended to Prove its Transmissibility, Charleston, 1840, p. 9).

The term "quarantine" derives from the Italian phrase, quaranta giorni, meaning forty days. From the time of the Black Death in the 1340s, the Italian city-states took the lead in what we would call public health. 

During plague epidemics, 15th century Venice began to enforce forty days' isolation on ships entering the port. Passengers and crew could not disembark until that period had ended with no cases appearing. Passengers stranded on cruise ships where coronavirus has broken out will understand what a terrible prospect that was. And modern cruise ships are far more comfortable and clean than ships of the past.

Other ports imitated Venice, and quarantine was later applied to other diseases such as smallpox, yellow fever, and cholera (from the 1830s). The length of quarantine then and since has varied, and is usually shorter than 40 days.

From the 15th century on, many ports created quarantine stations for isolation. These were sometimes on ships, on islands in or near the harbor, or on the mainland at a distance from highly populated areas. Some were old leper hospitals, often know as lazar houses, after the biblical parable of the beggar Lazarus. The stations established to quarantine for plague were often called lazarettos or pest houses -- "pest" coming from the French for plague, la peste. Venice established the first lazaretto in 1403 on one of the nearby islands. (Below: one of Venice's lazarettos and that in Ancona, also in Italy).

The oldest surviving quarantine station in the United States dates from 1799. and is near Philadelphia (below). American ports began establishing pest houses about a century earlier.

Inland localities have often used a cordon sanitaire to restrict movement of people in and out of a town or region, where an epidemic was underway. The authorities close off the access points to and from the place to prevent infected people from spreading the disease. In effect, the whole population inside the cordon was quarantined.

Sanitary cordons were a common measure used to prevent the spread of cholera in the 19th century, and are being used again to curb or slow the spread of the coronavirus. China has used them in the city of Wuhan and Province of Hubei during the current coronavirus outbreak. Italy has cordoned off some towns in the North ("lockdown"), then the North as a whole, and now the entire country.

In most cases where a cordon sanitaire has been used, communities have been isolated against their will. But in at least one famous case, in 1665, the inhabitants of a village agreed to cordon themselves off to protect neighboring towns and villages. In that case, the disease was plague. The village was Eyam in Derbyshire, England. The isolation lasted more than a year and killed at least 260 people, possibly more than half the residents who remained. But the disease did not spread beyond the parish boundaries.

During major epidemics, public facilities for quarantining and caring for the infected often became overwhelmed. Authorities often commandeered private houses or other buildings as temporary pest houses or hospitals for the specific disease, such as plague, smallpox, yellow fever, etc. The image below is of a pest house and plague pit in London's Finsbury Fields. The image dates from 1865 but depicts an earlier period, probably the Great Plague of London in 1665. The plague pit next to the pest house can hardly have been reassuring, but the case mortality rate from plague ranged from about 60-90 percent.

Today, many countries are trying to combat the spread of coronavirus by urging people who think they may be infected or are especially vulnerable, to self-isolate at home. Authorities did the same in earlier times, especially during plague epidemics from the 14th century. The isolation was seldom voluntary. Families were often forcibly shut up when one or more became infected. This could be a death sentence for all of them. Daniel Defoe provides a harrowing description of their suffering in A Journal of the Plague Year (1721), a fictionalized account of the Great Plague of London in 1665.

In conclusion, most of the quarantine measures used today have historical parallels. Just as in the past, quarantine may prove more successful in some places than others. We may have the advantage of a better understanding than our ancestors of how many contagious diseases spread, but in the case of coronavirus, we are battling a microbe that is new and somewhat mysterious.


  1. Thank you for that informative historical account. I gather Jesus raised Lazarus from the dead but I don't know why that would apply to leper houses. I was wondering about the history of covic-19. How do they know absolutely it is a totally new virus - it could have existed in some remote part. I guess it is because it does not have traces of human DNA.

  2. I think the term lazaretto was probably to comfort people with the idea that they might find new life. I think that the term new virus is used because it is new to humans. It might be new to animals as well.