By Olivier Thibault
Quarantines and cordons sanitaires, such as those being imposed on Chinese cities to contain the new coronavirus, were developed to respond to major outbreaks of disease in the Middle Ages.
Here is a look back.
Only in rare cases in history have restrictions on human movement been imposed to contain disease on such a scale as being seen China—where 13 cities are in lockdown, affecting 40 million people.
Both were in China and India, countries with large populations, French health history specialist Patrick Zylberman told AFP.
The most recent was during the 2002-2003 outbreak of SARS (Severe Acute Respiratory Syndrome), which started in China and then spread across the world, claiming nearly 800 lives.
Such restrictions were also imposed during the late 19th century outbreak of bubonic plague in Mumbai, which killed thousands, Zylberman said.
Similar measures were also imposed during the 2013-2016 Ebola epidemic in West Africa when borders were closed and quarantine measures imposed, including on ships, animals, and people.
Six million people from Sierra Leone, one of the three hardest-hit countries, were forced to remain at home for three days in September 2014 and in March 2015 in a bid to halt the epidemic.
The terms quarantine and cordon sanitaire, which has a French origin but has become part of the English language, are sometimes used interchangeably but are different.
Quarantine is "a state, period or place of isolation, in which people or animals that have arrived from elsewhere or been exposed to infectious or contagious disease are placed," according to the Oxford dictionary.
The "cordon sanitaire" involves blocking and monitoring the entry and exit points in an area affected by an epidemic, as is currently the situation in China's Hubei province.
The word quarantine is drawn from Italian for 40 days and refers to a period of isolation that was used during the plagues of the 14th and 15th centuries.
The first documented cases involved ships coming from Dubrovnik in Croatia in 1377 and Venice in 1423 which were kept isolated outside of the cities to see if symptoms of the disease developed before they were allowed entry.
Mass quarantines were regularly used in Europe including during a cholera pandemic in the 1830s.
The term was first used in France in the 19th century when Paris sent 30,000 soldiers to block the border with Spain to prevent the arrival of yellow fever.
But the practice had been in use even before during big plagues.
In southeastern France, a 27-kilometer (16-mile) brick "plague wall", with guard posts, was built in the Vaucluse Mountains in 1721 to stop the spread of a plague that was striking surrounding regions.
In England in 1665, the village of Eyam voluntarily imposed a cordon sanitaire on itself after an outbreak of bubonic plague in order to protect the wider region, said Tom Solomon, emerging diseases specialist at Britain's Liverpool University.
Risk of panic
Solomon said restrictions on movement can be "counterproductive", leading people to panic and flee at any cost.
They can also unleash social unrest, as was the case during the Mumbai plague when people were forcibly admitted to hospital irrespective of their caste or gender, Zylberman said.
More recently, the SARS epidemic in China in 2003 led to violent riots and demonstrations in the eastern regions of Nankin and Shanghai in response to harsh quarantine conditions, he said.