The following is from the glossary at the end of the book from my first novel, The Simurgh And The Nightingale see: http://deworde.blogspot.com/2009/01/simurgh-and-nightingale-novel.html
Plague (Ch.3) is caused by a small bacterial bacillus Yersinia pestis which on occasions can look like a safety pin. It occurs primarily in rodents and is transmitted to man by fleas or by between people by airborne droplet infection. There are three types of infectious presentation. The first and commonest type, called bubonic, is characterised by the development of swellings or buboes particularly in the groin and armpits. This type requires the flea as a vector. The second and third types are pneumonic and septicaemia plague both of which are highly fatal. Infection in these types is caused by person to person contact. Plague was thought to have originated in the Caucasus and then spread along developing trade routes. Generally sporadic in outbreak, catastrophic pandemics such as the Black Death that hit Europe from 1348 to 1350 killed about a quarter of the entire population. That particular outbreak began in Caffa in the Crimea and spread along sea-routes to other Black Sea and Mediterranean ports. Incubation varies from a few hours to twelve days and people developing the pneumonic or septicaemia types would die within 48 hours.
The traditional response of rich communities to a reported outbreak of plague was to ‘leave quickly, go far away and return late’, leaving the poor to suffer most. It was not until after the cost of the Black Death to their populations that governments began to introduce measures to contain the infection. Venice introduced detention of ship’s crews for thirty days - the trentina - in 1374 and extended this to forty days - the quarantina - quarantine period (Chs.3,39) in 1403. In August 1423, Venice established the Lazzaretto Vecchio on the island of Santa Maria de Nasova for the detention of foreign traders and those who were actually sick. The original name was Nazaretto in deference to the hospice for pilgrims from Palestine that already existed on the island but it soon adopted the name of the institutions that had previously been established to isolate lepers, the Lazar houses or lazzarettos. By 1500 Venice had four distinct isolation units including the Lazzaretto Nuovo (Ch.3) which was established on Saint Erasmo island in 1468. It was in the same year that the authorities in Milan confirmed the true contagious nature of the disease by organising the first comprehensive contact tracing epidemiological study.
In 1377, the Great Council of the Republic of Ragusa, which had become independent of Venice overlordship in 1358, passed a law establishing a trentino, or thirty-day isolation period. The 4 tenets of this law were as follows:
(1) that citizens or visitors from plague-endemic areas would not be admitted into Ragusa until they had first remained in isolation for 1 month;
(2) that no person from Ragusa was permitted go to the isolation area, under penalty of remaining there for 30 days;
(3) that persons not assigned by the Great Council to care for those being quarantined were not permitted to bring food to isolated persons, under penalty of remaining with them for 1 month; and
(4) that whoever did not observe these regulations would be fined and subjected to isolation for 1 month. (adapted from: Sehdev PS. The History of Quarantine. CID (2002) 35; 1071-1072)
Ports, and the ships that sailed from them, were the greatest source of spread and all boats entering Venetian and Genovese waters had to display a flag - the patent (Ch.39) - showing they were free from disease and a certificate - the pratticke (Ch.39) - from their home port’s health authorities, proving it. Even today sailing boats on entering a foreign port hoist a small yellow quarantine flag which remains aloft until inspected by the port authorities.