When you're fighting off a cold or flu, it's easy to imagine the battle is being waged solely inside the confines of your body. But in order to spread, pathogens rely on nearly every aspect of our shared societies. Food and drink, social customs, our proximity to animals, urban design, income inequality: The science of epidemiology connects them all. Patient Zero investigates the spaces where people and pathogens collide. Learn more at www.patientzeropodcast.com. A production of New Hampshire Public Radio.