That was thought at one time (it was a popular new theory when we were writing our 14th century novels) we decided to go with the original theory and are glad we did because the DNA shows it was NOT Ebola or related disease but actually the various forms of traditional Yersinia pestis. However, that was only established by tests on several European "Plague Pit" burials that was published a few months ago, so older articles are going to refer to it. It also turned out that at least in London the lung (air born) version of pneumonic plague, played a great role than expected; but then this disease can present in a lot of ways (and a variety of symptoms). Until a couple of years ago, doctors and medical historians were "sure" that the Plague of Justinian (around the start of the Dark Ages) was NOT caused by Yersinia Pestis because the symptoms were so different than any known outbreak, including the 14th century but DNA showed THAT IT WAS YERSINIA PESTIS; so the danger of this disease it is can morph an it has a version that does affect the blood which can "bleed" like Ebola, hence the confusion.