Dancing Around the Four Sides

People are a little too fond of speculating without examining the facts. There is another form of plague (septicemic plague) that would produce symptoms similar to those of Ebola. It's perfectly well known, and *still* a form of Yersinia pestis (which you have to give credit for being a damnably flexible infectious agent).

Could it have been something other than Yersinia? Yes, though given the evidence it's unlikely. Could it have been Ebola? Very, very *unlikely*. The original transmission vector is *fruit* bats (not the European insectivorous species), which then infect animals which touch the fruit bats have dropped (the infectious vector is the saliva). Ebola is deadly in primates, swine, and deer. Humans contracted the disease from contact with the other animals (mostly prey species/bush meat -- because primates are regularly consumed in Africa). All of this doesn't point to something that could have appeared and disappeared like that in Europe. In addition, the initial infectious wave of such deadly, highly contagious diseases is usually *highly* lethal, and then subsequent waves become less intense. The initial Zaire wave of Ebola in 1976 was the most deadly encountered, with subsequent outbreaks declining in impact. This would indicate (circumstantially) that it was the earliest -- and previous waves of infection in the area would certainly have been recorded.

In short? Ebola as a postulate is fairly absurd, as I haven't noticed colonies of fruit bats in northern Europe.