origin+and+causes

====The black plague's origin was in the Gobi desert, and it started in the late 1320's. This disease is caused by a bacillus that was carried by fleas that were carried by rats, and it quickly spread to humans. When the rodent population invades the human habitats, or when humans invade rodent habitats, the infected fleas on the rodents will bite humans. If someone was to get bit by one of the fleas, they would get the disease. Once the infected human breathes, its easy for other people to get the disease from the air. ====

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