susan desmond helman who heads the bill and melinda gates foundation also participates. [ applause ] >> well, good morning. >> good morning. >> we're going to get right to the worst case scenario here. i don't know how many of you have seen the movie "contagion," i watched it again recently and got scared. one of the things i wanted to start with is by asking how close are we in the infectious disease world to a scenario like that? i'm going to start with you, dr. frieden. we've seen ebola, we're dealing with zika. there all these new tropical emerging infectious diseases coming out of the swamps. how close are we to something that can't be contained, some biblical plague? >> well, first off, every year on average we identify one new pathogen. and every day on average we at cdc start an investigation that could detect a new pathogen. the contagion scenario is a pandemic influenza. that's, frankly, what worries us most. bill gates has said there are only two things that could kill ten million people around the world, nuclear war and a biological event, either intentional or natural. a