The word quarantine comes from what may have been the only medical advance during the dismal period of the Black Death in Europe. In 1374, three officials were appointed to inspect all ships entering the port of Venice. They turned away all ships that had sick people on board.
Three years later, in the Italian seaport of Ragusa, officials isolated and detained all travelers for 30 days (called trentini giorni) and monitored them for signs of illness. Soon, however, they found that 30 days was not enough time, and the isolation period was lengthened to 40 days (quarante giorni) — the origins of the word quarantine.
Although mass quarantine for disease control was essentially abandoned in the early 1900s, it was still used during the 2002-2003 SARS epidemic. Epidemiologists (experts in the spread of disease) are still debating whether it effectively helped to control the spread of disease.