Felix Key in the Bayerischer Rundfunk podcast "IQ - Science and Research".
The mere word "plague" is enough to make you shudder. It is one of the deadliest epidemics - and not just because of the devastating plague epidemics in late antiquity and the Middle Ages. Even in the 19th and early 20th centuries, it killed twelve million people. And even today, the plague has not been eradicated, although the pathogen, Yersinia pestis, originates from a harmless intestinal bacterium. How did it develop into a killer?