Recent events have taught all of us that it is not a matter of if a major pandemic will strike, but when. As with many of the terms we hear, pandemic instantly puts a not in our stomachs. To explain what a pandemic really is, and what you and your family can do to protect yourselves, we talk with Dr. Dennis Perotta, Associate Director of Emerging Infectious Diseases at the National Center for Emergency Preparedness. Dr. Perotta has spent his entire career tracking epidemics, and shares with us what he thinks is the most frightening case we may face in the future.