Paul Louis Simond

Paul Louis Simond was a French scientist and biologist known for his work in understanding disease transmission. In the late 1800s, he demonstrated that fleas played a critical role in spreading the plague by transmitting Yersinia pestis, the bacteria responsible. This discovery helped scientists better understand how diseases spread and laid the groundwork for modern epidemiology. His research was instrumental in identifying vectors—the carriers of disease—in controlling outbreaks and preventing the spread of infectious illnesses.