Short Answer:
The Black Death was a bacterial disease.
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LONG ANSWER:
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The Black Plague was a serious bacterial infection that's transmitted primarily by 'fleas'. The organism that causes plague, Yersinia pestis, lived in 'small rodents' found most commonly in rural and semirural areas of Africa, Asia and the United States. It was believed to have started in China in 1334, spreading along trade routes and reaching Europe via Sicilian ports in the late 1340s. The plague killed approximately 25 million people, almost a third of the continent's population at the time. This was most likely one of the most devastating epidemics known in human history.
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