“In March 2014, Ebola was first found in rural Guinea and spread to rural Liberia. Then by the summer, as people came to Liberia’s capital, Monrovia, to seek care, Ebola started growing exponentially there. By November, sick people were going back to their villages, causing hotspots of the disease in rural areas that had been fine. Epidemiologists call it “ping-ponging.” This story takes listeners on a journey to understand how this happens — and how to stop it.”