They knew that people could spread the disease. History of Quarantine - http://www.cdc.gov/quarantine/historyquarantine.html http://www.cdc.gov/quarantine/hist

They knew that people could spread the disease. History of Quarantine - http://www.cdc.gov/quarantine/historyquarantine.html http://www.cdc.gov/quarantine/historyquarantine.html > The practice of quarantine, as we know it, began during the 14th century > in an effort to protect coastal cities from plague epidemics. The Origin of Quarantine - http://cid.oxfordjournals.org/content/35/9/1071.long http://cid.oxfordjournals.org/content/35/9/1071.long > societies have, since ancient times, used strategies to isolate persons with > disease from unaffected persons. Some of the earliest references to these > strategies are found in the books of the Old Testament. > ... > The profound impact of the epidemic (the plague) led to the institution of > extreme infection-control measures. For example, in 1374, Viscount Bernabo... > declared that every person with plague be taken out of the city into the > fields, there to die or to recover.