A quarantine is a restriction on the movement of people and goods which is intended to prevent the spread of disease or pests. It is often used in connection to disease and illness, preventing the movement of those who may have been exposed to a communicable disease, but do not have a confirmed medical diagnosis. It is distinct from medical isolation, in which those confirmed to be infected with a communicable disease are isolated from the healthy population. Quarantine considerations are often one aspect of border control.
The concept of quarantine has been known since biblical times, and is known to have been practised through history in various places. Notable quarantines in modern history include that of the village of Eyam in 1665 during the bubonic plague outbreak in England; East Samoa during the 1918 flu pandemic; the 1972 Yugoslav smallpox outbreak, and extensive quarantines applied throughout the world during the COVID-19 pandemic.
Ethical and practical considerations need to be considered when applying quarantine to people. Practice differs from country to country. In some countries, quarantine is just one of many measures governed by legislation relating to the broader concept of biosecurity; for example Australian biosecurity is governed by the single overarching Biosecurity Act 2015.

Etymology and terminology

The word quarantine comes from quarantena, meaning "forty days", used in 14th–15th-century Venetian and designating the period that all ships were required to be isolated before passengers and crew could go ashore during the Black Death plague epidemic; it followed the trentino, or thirty-day isolation period, first imposed in 1347 in the Republic of Ragusa, Dalmatia.
Merriam-Webster gives various meanings to the noun form, including "a period of 40 days", several relating to ships, "a state of enforced isolation", and as "a restriction on the movement of people and goods which is intended to prevent the spread of disease or pests". The word is also used as a verb.
Quarantine is distinct from medical isolation, in which those confirmed to be infected with a communicable disease are isolated from the healthy population.
Quarantine may be used interchangeably with cordon sanitaire, and although the terms are related, cordon sanitaire refers to the restriction of movement of people into or out of a defined geographic area, such as a community, in order to prevent an infection from spreading.



An early mention of isolation occurs in the Biblical book of Leviticus, written in the seventh century BC or perhaps earlier, which describes the procedure for separating out infected people to prevent spread of disease under the Mosaic Law:
If the shiny spot on the skin is white but does not appear to be more than skin deep and the hair in it has not turned white, the priest is to isolate the affected person for seven days. On the seventh day the priest is to examine him, and if he sees that the sore is unchanged and has not spread in the skin, he is to isolate him for another seven days.

Medieval Islamic world

The Islamic prophet Muhammad advised quarantine: "Those with contagious diseases should be kept away from those who are healthy." Ibn Sina also recommended quarantine for patients with infectious diseases, especially tuberculosis.
The mandatory hospital quarantine of special groups of patients, including those with leprosy, started early in Islamic history. Between 706 and 707 the sixth Umayyad caliph Al-Walid I built the first hospital in Damascus and issued an order to isolate those infected with leprosy from other patients in the hospital. The practice of mandatory quarantine of leprosy in general hospitals continued until the year 1431, when the Ottomans built a leprosy hospital in Edirne. Incidents of quarantine occurred throughout the Muslim world, with evidence of voluntary community quarantine in some of these reported incidents. The first documented involuntary community quarantine was established by the Ottoman quarantine reform in 1838.

Medieval Europe

The word "quarantine" originates from quarantena, the Venetian language form, meaning "forty days". This is due to the 40-day isolation of ships and people practised as a measure of disease prevention related to the plague. Between 1348 and 1359, the Black Death wiped out an estimated 30% of Europe's population, and a significant percentage of Asia's population. Such a disaster led governments to establish measures of containment to handle recurrent epidemics. A document from 1377 states that before entering the city-state of Ragusa in Dalmatia, newcomers had to spend 30 days in a restricted place waiting to see whether the symptoms of Black Death would develop. In 1448 the Venetian Senate prolonged the waiting period to 40 days, thus giving birth to the term "quarantine". The forty-day quarantine proved to be an effective formula for handling outbreaks of the plague. Dubrovnik was the first city in Europe to set up quarantine sites such as the Lazzarettos of Dubrovnik where arriving ship personnel were held for up to 40 days. According to current estimates, the bubonic plague had a 37-day period from infection to death; therefore, the European quarantines would have been highly successful in determining the health of crews from potential trading and supply ships.
Other diseases lent themselves to the practice of quarantine before and after the devastation of the plague. Those afflicted with leprosy were historically isolated long-term from society, and attempts were made to check the spread of syphilis in northern Europe after 1492, the advent of yellow fever in Spain at the beginning of the 19th century, and the arrival of Asiatic cholera in 1831.
Venice took the lead in measures to check the spread of plague, having appointed three guardians of public health in the first years of the Black Death. The next record of preventive measures comes from Reggio/Modena in 1374. Venice founded the first lazaret in 1403. In 1467 Genoa followed the example of Venice, and in 1476 the old leper hospital of Marseille was converted into a plague hospital. The great lazaret of Marseille, perhaps the most complete of its kind, was founded in 1526 on the island of Pomègues. The practice at all the Mediterranean lazarets did not differ from the English procedure in the Levantine and North African trade. On the arrival of cholera in 1831 some new lazarets were set up at western ports, notably a very extensive establishment near Bordeaux, afterwards turned to another use.

Modern history

. Source: National Maritime Museum of Greenwich, London
Epidemics of yellow fever ravaged urban communities in North America throughout the late-eighteenth and early-nineteenth centuries, the best-known examples being the 1793 Philadelphia yellow fever epidemic and outbreaks in Georgia and Florida. Cholera and smallpox epidemics continued throughout the nineteenth century, and plague epidemics affected Honolulu and San Francisco from 1899 until 1901. State governments generally relied on the cordon sanitaire as a geographic quarantine measure to control the movement of people into and out of affected communities. During the 1918 influenza pandemic, some communities instituted protective sequestration to keep the infected from introducing influenza into healthy populations. Most Western countries implemented a range of containment strategies, including isolation, surveillance, and the closure of schools, churches, theatres and public events.
whose inhabitants believe that doctors poison those suspected of cholera
By the middle of the 19th century, the Ottoman Empire had established quarantine stations, including in Anatolia and the Balkans. For example, at the port of Izmir, all ships and their cargo would be inspected and those suspected of carrying the plague would be towed to separate docks and their personnel housed in separate buildings for a determined period of time. In Thessaly, along the Greek-Turkish border, all travellers entering and exiting the Ottoman Empire would be quarantined for 9–15 days. Upon appearance of the plague, the quarantine stations would be militarised and the Ottoman army would be involved in border control and disease monitoring.

International conventions 1852–1927

Since 1852 several conferences were held involving European powers, with a view to uniform action in keeping out infection from the East and preventing its spread within Europe. All but that of 1897 were concerned with cholera. No result came of those at Paris, Constantinople, Vienna, and Rome, but each of the subsequent ones doctrine of constructive infection of a ship as coming from a scheduled port, and an approximation to the principles advocated by Great Britain for many years. The principal countries which retained the old system at the time were Spain, Portugal, Turkey, Greece and Russia. The aim of each international sanitary convention had been to bind the governments to a uniform minimum of preventive action, with further restrictions permissible to individual countries. The minimum specified by international conventions was very nearly the same as the British practice, which had been in turn adapted to continental opinion in the matter of the importation of rags.
The Venice convention of 30 January 1892 dealt with cholera by the Suez Canal route; that of Dresden of 15 April 1893, with cholera within European countries; that of Paris of 3 April 1894, with cholera by the pilgrim traffic; and that of Venice, on 19 March 1897, was in connection with the outbreak of plague in the East, and the conference met to settle on an international basis the steps to be taken to prevent, if possible, its spread into Europe. An additional convention was signed in Paris on 3 December 1903.
A multilateral international sanitary convention was concluded at Paris on 17 January 1912. This convention was most comprehensive and was designated to replace all previous conventions on that matter. It was signed by 40 countries, and consisted of 160 articles. Ratifications by 16 of the signatories were exchanged in Paris on 7 October 1920. Another multilateral convention was signed in Paris on 21 June 1926, to replace that of 1912. It was signed by 58 countries worldwide, and consisted of 172 articles.
In Latin America, a series of regional sanitary conventions were concluded. Such a convention was concluded in Rio de Janeiro on 12 June 1904. A sanitary convention between the governments of Argentina, Brazil, Paraguay and Uruguay was concluded in Montevideo on 21 April 1914. The convention covers cases of Asiatic cholera, oriental plague and yellow fever. It was ratified by the Uruguayan government on 13 October 1914, by the Paraguayan government on 27 September 1917 and by the Brazilian government on 18 January 1921.
Sanitary conventions were also concluded between European states. A Soviet-Latvian sanitary convention was signed on 24 June 1922, for which ratifications were exchanged on 18 October 1923. A bilateral sanitary convention was concluded between the governments of Latvia and Poland on 7 July 1922, for which ratifications were exchanged on 7 April 1925. Another was concluded between the governments of Germany and Poland in Dresden on 18 December 1922, and entered into effect on 15 February 1923. Another one was signed between the governments of Poland and Romania on 20 December 1922. Ratifications were exchanged on 11 July 1923. The Polish government also concluded such a convention with the Soviet government on 7 February 1923, for which ratifications were exchanged on 8 January 1924. A sanitary convention was also concluded between the governments of Poland and Czechoslovakia on 5 September 1925, for which ratifications were exchanged on 22 October 1926. A convention was signed between the governments of Germany and Latvia on 9 July 1926, for which ratifications were exchanged on 6 July 1927.
One of the first points to be dealt with in 1897 was to settle the incubation period for this disease, and the period to be adopted for administrative purposes. It was admitted that the incubation period was, as a rule, a comparatively short one, namely, of some three or four days. After much discussion ten days was accepted by a very large majority. The principle of disease notification was unanimously adopted. Each government had to notify to other governments on the existence of plague within their several jurisdictions, and at the same time state the measures of prevention which are being carried out to prevent its diffusion. The area deemed to be infected was limited to the actual district or village where the disease prevailed, and no locality was deemed to be infected merely because of the importation into it of a few cases of plague while there has been no diffusion of the malady. As regards the precautions to be taken on land frontiers, it was decided that during the prevalence of plague every country had the inherent right to close its land frontiers against traffic. As regards the Red Sea, it was decided after discussion that a healthy vessel could pass through the Suez Canal, and continue its voyage in the Mediterranean during the period of incubation of the disease the prevention of which is in question. It was also agreed that vessels passing through the Canal in quarantine might, subject to the use of the electric light, coal in quarantine at Port Said by night as well as by day, and that passengers might embark in quarantine at that port. Infected vessels, if these carry a doctor and are provided with a disinfecting stove, have a right to navigate the Canal, in quarantine, subject only to the landing of those who were suffering from plague.