Quarantine

Summary

Quarantine — holding people, ships, or goods suspected of carrying disease apart from the healthy population for a fixed period — is one of the oldest tools of organized public health, and the one that most directly raises the tension between individual liberty and collective protection. The word comes from the Italian quarantenaria, meaning a forty-day period of detention first formalized by the Adriatic port of Ragusa in 1377. Before Ragusa codified the practice, medieval cities had managed plague through ad hoc segregation of the sick, the closing of infected houses, and the expulsion of lepers. What the Italian city-states added was institutional permanence: a standing authority empowered to detain ships, burn cargo, and confine healthy travelers alongside sick ones. The practice rested on wrong theory — miasma, not contagion — yet it worked well enough to become the template for every epidemic response that followed. Quarantine also had a larger cultural consequence: practices such as inoculation and quarantine, combined with new drugs like quinine and opium, boosted confidence in medicine’s ability to identify, understand, and fight disease. These measures did not supplant the divine meanings attached to death — but they increasingly provided an alternative language for thinking and talking about death, one grounded in human intervention rather than divine decree.(Jackson (ed.), 2011)

Origins: Leprosy and the Logic of Exclusion

The principle that persons carrying communicable disease must be separated from the community did not begin with plague. It began with leprosy. George Rosen, whose History of Public Health (1958) remains the standard account, identifies the medieval response to leprosy as “the first great feat in direct prophylaxis, namely, methodical eradication of disease by consistently making the affected individuals harmless as carriers of the causative element.”(George Rosen, 1993) The Council of Lyons in 583 CE restricted the free movement of lepers among healthy persons, and subsequent Church councils developed this policy further.(George Rosen, 1993) By the beginning of the thirteenth century, France alone had approximately 2,000 leprosaria; throughout Europe, they numbered around 19,000.(George Rosen, 1993)

What gave leper exclusion its shape was not medical knowledge — physicians had almost nothing useful to offer — but the Old Testament. As Erwin Ackerknecht observes in his Short History of Medicine (1955), “The Old Testament is far more contagion-minded than the Greek classics,” and medieval Europe, “pervaded by biblical tradition, developed a better understanding of contagiousness than was evidenced in late antiquity.”(Ackerknecht, 1955) Leviticus provided the charter for exclusion: the person with skin disease must dwell outside the camp, cry “unclean,” and keep apart. This framework, Rosen argues, was “amplified and carried further in dealing with that other great scourge of the Middle Ages known as the bubonic plague.”(George Rosen, 1993) In a later chapter of the same work, Rosen makes the underlying principle explicit: leper isolation was “the first systematic application of compulsory segregation of communicable disease patients,” developing the principle that “remains in public health today.”(George Rosen, 1958)

John Simon, writing from his long experience as the first Medical Officer of Health for London in English Sanitary Institutions (1890), traced this same tradition further back — to the Hebrew Pentateuch’s explicit requirement that “persons who have contagious disease must be restricted from common intercourse.”(John Simon, 1890) Medieval London enforced strict leper exclusion from the fourteenth century: a royal ordinance of 1346 ordered all persons with leprosy to leave the city within fifteen days; by 1375, the porters of the city’s eight gates were sworn individually not to allow any leper to enter.(John Simon, 1890)

The Black Death and the Birth of Formal Quarantine

The Black Death reached European ports in 1348, carried on Genoese ships from Caffa on the Black Sea, and swept through the continent in approximately three years, killing between one-third and one-half of the population it encountered.(George Rosen, 1993) Nothing in Galenic medicine addressed plague; Ackerknecht notes flatly that “nothing concerning plague could be found in Galen.”(Ackerknecht, 1955) The response, therefore, had to come from elsewhere — from biblical tradition, from commercial self-interest, and from the practical observation that plague seemed to travel with people and goods.

Venice moved first. On March 20, 1348, a council of three men was established to supervise the health of the city.(George Rosen, 1993) In 1374, Venice denied entry to travelers coming from infected areas. Then, on July 27, 1377, the municipal council of Ragusa on the Dalmatian coast ordered a thirty-day period of isolation — trentino — for all persons arriving from plague-affected regions.(George Rosen, 1993) Rosen, drawing on the same documentary record as the Venice historian Jane Crawshaw, fixes this date as the origin of formalized quarantine as an institution.(George Rosen, 1958) The period was later extended to forty days — quarantina giorni — from which the English word derives. In 1383, Marseilles erected the first permanent French quarantine station, detaining travelers and cargoes from suspected ships for forty days and exposing them to open air.(George Rosen, 1958)

Why forty days? Rosen offers an account drawn from the historian Hecker: during the thirteenth and fourteenth centuries, the fortieth day was “generally considered the day of separation between the acute and chronic forms of disease.”(George Rosen, 1993) Biblical numerology reinforced the choice — the Flood lasted forty days, as did multiple other biblical episodes — and alchemical tradition held that forty days were needed for certain transmutations.(George Rosen, 1993) Medical theory, scripture, and natural philosophy converged on the same number, giving it an authority no single tradition alone could have provided.

Venice went further than any other city in building permanent institutions. Simon’s account in English Sanitary Institutions — written from long administrative experience rather than from archives alone — records that Venice established its first lazaretto in 1423, an extended new one in 1467, and a permanent health magistracy in 1485; by 1556, offices of superintendency had been added to this machinery, and the regulations it enforced “were of high repute in Europe.”(John Simon, 1890) The lazaretto was the physical infrastructure of quarantine: a purpose-built facility, usually on an island or at the edge of a city, where detained travelers, goods, and crew could be held and aired without contact with the healthy population. The word comes from Santa Maria di Nazaret, the Venetian island where the first isolation hospital was established — and from Lazzaro, the biblical name for the leper.

The Lazaretto System

What the Italian city-states built between the 1370s and the 1550s was not merely a set of rules but a system with administrative infrastructure, legal force, and physical plant. Rosen’s account of the Italian achievement, confirmed by Carlo Cipolla’s detailed studies of plague administration in Tuscany, establishes that the response to the Black Death and successive epidemics “drove the creation of quarantine, isolation hospitals, and permanent public health boards in 14th-15th century Italy — institutions that became the template for modern public health administration.”(George Rosen, 1958)

The intellectual basis of the system was miasmatic, not contagionist. Medieval epidemic theory, as Rosen summarizes, held that “some atmospheric alteration, a corruption of the air, brought on the disease… caused by decaying organic matter, stagnant and putrid waters, and the like.” Mass outbreaks resulted when “a malign conjunction of the stars caused the atmospheric corruption to become especially virulent.”(George Rosen, 1993) This was the dominant Hippocratic-Galenic framework, and it remained so until the late nineteenth century. Yet miasmatic theory was not as obviously incompatible with quarantine as it might seem: if miasma attached to goods, clothing, and ships as well as to air, then detaining and airing those objects made sense within the theory. The famous practice of fumigating mail and goods with vinegar and aromatic smoke was a direct application of miasmatic logic to the management of suspected fomites. Yet even within this miasmatic framework, the Italian system was anticipating the fomites concept that Girolamo Fracastoro would articulate theoretically in 1546 — Fracastoro’s treatise De Contagione described epidemic diseases caused by “minute infective agents transmissible by direct contact, intermediate objects (fomites), or at a distance through the air,” which Rosen calls “the first consistent theory of contagious disease.”(George Rosen, 1958)

Some medieval physicians saw further than the standard miasmatic account. Michael W. Dols, in The Black Death in the Middle East (1977), documents that Lisan ad-Din ibn al-Khatib of Granada wrote a plague treatise arguing explicitly for contagion — not miasma — as the primary mechanism of plague transmission, supporting this claim with “extensive observational evidence: isolated communities that had no contact with the sick were spared; travelers who arrived in plague-stricken areas contracted the disease; plague spread along trade routes; and infected clothing and goods transmitted the disease.”(Michael W. Dols, 1977) Ibn al-Khatib reached this conclusion before European physicians had articulated anything comparable, but his theory was rejected by Islamic religious authorities because it contradicted the hadith prohibition on flight from plague.(Michael W. Dols, 1977)

The European quarantine system, by contrast, was underpinned by religious tradition — biblical rather than Quranic — that actually encouraged separation of the diseased. The institutional development that followed was, as Rosen observes in his History of Public Health (1993), a case in which “public health organization and administration remained essentially unchanged from medieval patterns throughout the sixteenth to eighteenth centuries despite the rapid growth of science” — meaning that quarantine spread and elaborated itself across Europe without benefit of, or need for, the new scientific discoveries of the period.(George Rosen, 1993)

Quarantine and State Power

Andrew Wear, a historian of early modern English medicine, shows in Knowledge and Practice in English Medicine (2000) that the dramatic community-wide measures of plague control — “quarantine, the shutting up of infected houses, the closing of lodging houses, inns and theatres, and the banning of fairs were ordered not by physicians but by governments and local authorities.”(Wear, 2000) Physicians provided advice; magistrates held the legal power. This division was not merely administrative convenience. It expressed something real about the nature of quarantine as an instrument: it is inherently coercive, and coercion requires political authority that physicians do not possess in their own right.

The policy of “shutting up” — practiced in London and most English cities through the 1665 Great Plague — was the most coercive of these measures, and among the most morally contested. When someone in a household was diagnosed with plague, Wear notes, “they and the healthy members of the household were shut up together in the house for forty-two days.”(Wear, 2000) This meant confining the healthy with the sick, preventing both from leaving, and posting watchmen at the door to ensure compliance. Medical writers and practitioners faced, as Wear puts it, “acute moral dilemmas” about whether this policy was “justified medically and morally.”(Wear, 2000) A family sealed with a plague patient had no choice but to breathe the same air, handle the same objects, and wait. Those who argued from miasmatic theory faced the obvious problem that they were recommending people remain in the very miasmatic environment that was supposed to cause the disease.

London experienced recurring plague between 1580 and 1665, and its stock measures — infected houses shut up with red crosses and watchmen posted, pest-houses provided for the sick, searchers appointed and paid to certify cause of deaths, night burials — were applied each time without fundamental change.(John Simon, 1890) Simon, tracing the development of English quarantine from the Stuart period forward, documents that the first serious proposals for maritime quarantine came during the plague threat of 1663-5. A lazaretto at Gravesend was proposed; vessels arriving from infected ports were to be detained and examined; medical inspection of incoming ships was attempted.(John Simon, 1890) These proposals were “on a far larger scale than anything previously conceived for London, though in execution they fell considerably short of what was planned.”(John Simon, 1890) The pattern — ambitious policy, inadequate implementation — recurred throughout the history of English quarantine administration.

The most systematic English elaboration of quarantine principles came from Richard Mead, whose 1720 pamphlet “A Short Discourse Concerning Pestilential Contagion” went through nine editions in its first year and became, as Simon puts it, “the standard text of plague policy.”(John Simon, 1890) Mead proposed a system including a Council of Health, rigid separation of sick from healthy, removal of infected families to airy lodgings at public expense, and destruction of infected goods.(John Simon, 1890) The Quarantine Act of 1721 (7 George I c.3) implemented Mead’s proposals into law, but commercial opposition and party animosity secured its partial repeal, and England remained, in Simon’s judgment, “without adequate quarantine legislation” for another century.(John Simon, 1890)

Critiques and Resistance

Quarantine was never without opponents, and the intellectual case against it was sometimes more coherent than the case for it. The most powerful objection was structural: quarantine regulations imposed enormous costs on trade and had to be enforced with coercion, but the evidence that they worked was difficult to assemble and easy to contest.

The ideological stakes rose sharply with the cholera epidemics of the nineteenth century. Simon records that in 1830, the English statute book contained “no general law of sanitary intention, except (so far as this deserves to be counted an exception) the Act providing for Quarantine.”(John Simon, 1890) When cholera arrived at Sunderland in autumn 1831, the British government initially extended quarantine regulations designed for plague to cover cholera.(John Simon, 1890) But the new Central Board of Health quickly “renounced the policy of the previous Board as to coercive restrictions of intercourse with infected or suspected persons or places: declaring that measures of coercion, when tried upon the Continent, had ‘invariably been productive of evil.’”(John Simon, 1890)

This reversal expressed a genuine theoretical disagreement, not merely political convenience. The dominant anti-contagionist position — held by Edwin Chadwick’s General Board of Health and by most of the British sanitary reform movement — was that epidemic diseases arose from an “epidemic atmosphere” affecting unsanitary localities, and that quarantine therefore “could not give any but a false security.”(John Simon, 1890) The Board recommended abolishing quarantine establishments entirely and relying instead on local sanitary improvements. They were wrong about the mechanism — cholera is transmitted by contaminated water, not atmosphere — but right that sanitary improvements reduced cholera mortality, and wrong that quarantine was useless. The consequence of their confident anti-contagionism was a generation of British public health reform focused on drainage and water supply rather than on disease-specific containment.

Mathew Carey, writing during the 1793 Philadelphia yellow fever epidemic, had articulated the tension between quarantine and republican governance with unusual clarity. John Powell, in his 1949 account of that epidemic, Bring Out Your Dead, reproduces Carey’s argument: “‘As the nature of our government did not allow the arbitrary measures to be pursued, which, in despotic countries, would probably have extinguished the disorder at an early period,’ Carey observed, those who could avoid the disease by flight saved the city and the doctors much labor by their departure.”(Powell, 1949) The corollary was uncomfortable but real: the more democratic a government, the more difficult it was to enforce the coercive containment measures that quarantine required. Pennsylvania’s legislature passed a new quarantine act in September 1793 and then immediately left the city.(Powell, 1949)

Dols’s account of the Islamic world offers a different kind of resistance. The hadith prohibition on flight from plague — “If you hear that plague is in a land, do not enter it; if it breaks out in a land where you are, do not leave it fleeing from it” — made any quarantine-equivalent policy, including cordon sanitaire, theologically objectionable within orthodox Sunni jurisprudence.(Michael W. Dols, 1977) The doctrine that dying of plague constituted martyrdom further discouraged flight and prophylactic measures that might imply distrust of divine will.(Michael W. Dols, 1977) What looks from the outside like resistance to public health measures was, within its own framework, a coherent theological position about fate, faith, and the limits of human intervention.

William McNeill, in Plagues and Peoples (1976), offers a comparative perspective on resistance to epidemic control from a different angle. He observes that traditional communities living in proximity to plague reservoirs had developed customary behaviors — analogous to quarantine in function if not in form — that effectively managed the risk: “Nomad tribesmen of the steppe region… had mythic explanations to justify epidemiologically sound rules for dealing with the risk of bubonic infection from marmots. Trapping was taboo; a marmot could only be shot. An animal that moved sluggishly was untouchable.”(McNeill, 1976) Modern scientific containment of plague, McNeill argues, was “a quite normal, though unusually speedy and effective, human response to epidemiological emergency” — science arriving at the same practical conclusions that folk tradition had reached through trial and error.(McNeill, 1976)

Modern Quarantine

The bacteriological revolution of the 1880s transformed the theoretical basis of quarantine without immediately transforming its practice. Once Koch had identified the cholera bacillus (1883) and the plague bacillus was identified by Yersin and Kitasato (1894), it became possible to argue for scientifically targeted containment rather than blanket detention. Quarantine could in principle become selective — applied to those demonstrably infected, not to every ship from a suspicious port.

The third plague pandemic of 1894-1924, spread by steamship along global trade routes, provided the crucible for this new approach. McNeill’s analysis is instructive: the “medical prophylaxis developed so successfully between 1894 and 1924” combined laboratory diagnosis, vector control (targeting rats and fleas), and selective isolation in a way that earlier systems had not been able to manage.(McNeill, 1976) The same network of steamship routes that spread plague globally also, for the first time, allowed coordinated international response.

The International Sanitary Conferences, beginning in 1851, had already begun the work of rationalizing quarantine across national boundaries — a recognition that the competitive disadvantage imposed by quarantine on trade made international agreement essential. The result was a slow negotiation between commercial interests, which wanted minimal quarantine, and public health interests, which wanted maximum security. The International Sanitary Conference convened at Constantinople in 1866 established India as the source of the cholera pandemics that had recently afflicted Europe and much of the rest of the world; the immediate cause of the 1865–6 pandemic was an outbreak of cholera in Mecca, widely attributed to pilgrims arriving from India — a finding that immediately shaped quarantine policy directed at pilgrimage routes.(Jackson (ed.), 2011) The 1892 International Sanitary Convention and subsequent agreements established frameworks that would eventually become the World Health Organization’s International Health Regulations.

The twentieth century did not abandon quarantine; it refined it. The WHO’s response to SARS in 2003, and the worldwide application of quarantine and isolation measures to COVID-19 in 2020, demonstrated that even in an era of antiviral therapy and rapid diagnostic testing, the basic logic of quarantine — separating potential carriers from the susceptible until the risk can be assessed — remains operationally necessary. What changed was the duration (shorter, calibrated to incubation periods now known precisely), the targeting (based on laboratory confirmation or exposure history), and the legal framework (human rights protections now set explicit limits on detention). What did not change was the structural tension that Carey identified in 1793: quarantine is coercive, coercion requires authority, and democratic governance makes that authority harder to exercise than plague administrators in fifteenth-century Venice found it.

See Also

• plague — the disease that drove the development of the formal quarantine system
• black-death — the 1348 pandemic that precipitated the Ragusa and Venice innovations
• public-health — the broader field of which quarantine is one instrument
• miasma-theory — the wrong theory under which quarantine was first rationalized
• leprosy — whose institutional management anticipated quarantine’s logic
• lazaretto — the physical infrastructure of quarantine detention
• contagion — the competing explanation for epidemic spread
• cholera — the disease that drove nineteenth-century debates over quarantine’s validity
• cordon-sanitaire — the land-based territorial equivalent of maritime quarantine
• boards-of-health — the administrative bodies that enforced quarantine

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