The bacterium Yersinia Pestis has been plaguing mankind for at least six thousand years. Generally referred to as the Black Plague the bacterium was recently found in human skeletons from Europe's Neolithic period. It has changed the course of civilizations several times and a recent (2021) study suggests it may have contributed to the collapse of Neolithic European civilization prior to steppe herders migrating to Europe and ushering in the Bronze Age.
—David Foss