The word “quarantine” comes from the Italian word “quaranta”, which means “forty”. At the height of the Venetian trading empire, one of the major threats that the city faced was the danger that foreign trade would bring in new diseases. Venice had 22 incidents of the black plague between 1361 and 1528. To minimize the risk of disease, the city instituted a rule that any ship which arrive to the city with signs of disease must be kept isolated offshore for long enough for the disease to run its course, generally 40 days. In time, separating out any disease for a prolonged period of time became known as a “quarantine”.
– A few thoughts from your friend Saxo