and that is part of the problem here to talk about that i'm joined by professor stephen morse he's an epidemiologist at columbia university professor good to have you on the program what are we seeing happening here we we hear that the piece of new cases in china is slowing but everywhere else in the world we're talking about a ballooning of new cases. this is the 1st time we've really tried to contain a respiratory infection that passes from person to person so if you think of flu pandemics for example we had one in 2009 we've never really tried to prevent it from spreading and it's always been an interesting question whether that was possible it takes a tremendous amount of effort to do it it's really a herculean task in terms of the public health effort to identify cases and then trace their contacts so that we can separate them from people who are already an infected this does spread about as well as the flu maybe is somewhat better so they sickly it's a very similar situation and a few people who slip by they're not identified or they may not be very sick as most of these people