Pause a moment to look at this dialog box from the Eclipse STEM project. STEM stands for the Spatiotemporal Epidemiological Modeler. Just looking over this dialog box, you should be able to understand what I'm after here. Just how bad can this swine flu get? I certainly don't know the answer, but I do know that we can all take time today to model the worst and best case scenarios in Eclipse. This is a really fun toy, I have to say. It's somewhat complex, but the folks behind it have written some great guides to make sure you know what you're doing.
First, you'll want to install STEM on top of Eclipse. You can download it here. Once you're up and running, the above dialog, which is relatively self explanatory, can be found in the terrific tutorial. There are a lot of other uses here, too. Have fun terrifying yourselves!