Talk:Rat Plague/@comment-3525200-20130610175004/@comment-3525200-20130611103417

Well a book you find in the game mentions at least a year; http://dishonored.wikia.com/wiki/The_Rat_Plague_%28book%29

Plus the plague was already bad before the Empress died, the other cities were going to blockade Dunwall according to the letter Corvo gave her.