http://wcbs880.com/topstories/topstories_story_074135149.html
CDC: A person usually becomes ill with bubonic plague 2 to 6 days after being infected.
When bubonic plague is left untreated, plague bacteria invade the bloodstream. As the plague bacteria multiply in the bloodstream, they spread rapidly throughout the body and cause a severe and often fatal condition. Infection of the lungs with the plague bacterium causes the pneumonic form of plague, a severe respiratory illness. The infected person may experience high fever, chills, cough, and breathing difficulty, etc.
I always heard that it was "up stairs, down stairs, we all fall down."
A buddy of mine transferred to England and he told me that the up stairs, down stairs was a class thing. The very poorest lived on the ground level. That stuff did not recognise class and the up stairs and down stairs were affected equally.