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Research suggests that the Bubonic Plague existed thousands of years before it caused widespread death in 14th century Europe. Danish researchers examining human teeth fossils have discovered evidence of the plague from almost 5,000 years ago. In the middle 1300s the disease killed 50 to 60 percent of Europe’s population. But the bacterium was not nearly as aggressive in its earlier form says the study leader Simon Rasmussen of Denmark’s Technical University. He helped examine 101 fossilized teeth from the Bronze Age, about 5,000 years ago. Only seven of those teeth contained evidence of the plague. This suggests the bacterium did not spread as easily then as it did later. Today, even infected fleas can pass the disease to humans. Rasmussen said the Bronze Age plague did not have the gene that makes it able to live in a flea. The Danish researchers had earlier reported on genomic studies of the plague. Those studies said the plague might have been part of widespread disease that led to the fall of Classical Greece and hurt the ancient Roman army. Rasmussen says the ancient epidemics may also have led to a number of mass migrations. Plague is rare today. A large outbreak happened in India in 1994 when almost 700 cases were reported. With early antibiotic treatment, Rasmussen says the plague is almost completely curable. The latest findings are published in the journal Cell.