The bubonic plague, a dangerous, often fatal disease, can be spread by the bite of fleas that have been infected by rats. The most famous plague epidemic, called the “black death,” began in the East in the 14th century and was spread to the West by Italian merchants, whose ships transported the rats and fleas back to Europe. The plague was thought to be communicable, so Western governments began requiring quarantines for incoming ships. On this date in 1348, Venice was the first city to approve a quarantine policy. An Italian physician named Simon de Covina helped devise a 30-day isolation period, known as a trentina.

Copyright Aetna InteliHealth, Inc., 2012. All rights reserved.