Questions about the Black Death

I've just watched this fascinating documentary (The Mistery of the Black Death) and thought I should recommend it here. I'd already watched some other pretty good [1] and [2] documentaries about this terrible disease that claimed the lives of between 1/3 and 1/2 of the European population of the time, so we could say that I had some basic common knowledge about it. This means that to me The Black Death was the same as Bubonic Plague, was caused by the Yersinia Pestis bacteria and transmitted by rat's fleas.
Well, if that's also what you think be ready to be shocked by this documentary.

The correlation between the Bubonic Plague and the Black Death was somehow established in the late XIX century after Alexander Yersin studied a Plague outbreak in Hong Kong and pinpointed Yersinia Pestis as the cause and rat's fleas as the vector. Scientists saw similarities enough between the symptoms and spread of both epidemics to link them together. This link would be quite comforting for the XX century men, cause as Bubonic Plague could be cured by antibiotics, there was no reason to be concerned about the mysterious Black Death making a come back.
However, this link seems to be fading away in the eyes of several scientists and historians. First of all, it does not seem possible that the common European rats of that time could transmit the illness to Northern Europe, second, the transmission speed of the Black Plague is way faster than that of the Bubonic Plague epidemics, and third, even the symptoms of both illnesses don't seem to be that similar as initially thought.

An old nightmare as it seems, the Black Death has been in the news in the last years for another surprising findings regarding it. A few years ago I watched this excellent documentary Secrets of the Great Plague where they talk about the relationship between immunity to the Black Death and immunity to HIV. While trying to find the link to the documentary, I found to my complete surprise that there's a quite older documentary, Secrets of the Death: Mystery of the Black Death that already called attention to the relationship between both diseases.

I can't finish off this post without mentioning this excellent film using the Black Death to undertake a brilliant attack on the religious establishment.