Earlier this month, we looked at the relative number of victims of various pandemics in history. Now let's find out more about those diseases. What illnesses were people most afraid of during different historical eras? There was leprosy, influenza, bubonic plague, syphilis, smallpox, cholera, tuberculosis, and COVID-19, but none of those existed by themselves, and even these diseases were sometimes misdiagnosed because there was always something else out there that wanted to kill you. And these deadly illnesses became epidemics because of close living conditions and poor sanitation in crowded cities. Our own sociability became a mass transit system for bacteria and viruses. Enhanced travel took diseases to other communities all around the world. If you worry about getting sick, just be thankful for modern science. Back when we couldn't figure out what was causing these diseases, much less prevent or treat them, your odds for surviving them were downright dismal.