Identifying the Origin of an Epidemic

My NICO colleague (and office mate) Dirk Brockmann has done some very cool work on identifying where an epidemic began by looking at how it has spread through airline networks. Centuries ago the spread of disease was constrained by geography (like the spread of obesity appears to be today). If you look at a map of where the disease has spread to over time, you could easily trace it back to it's origin — the epidemic just spreads out like ripples in a pond. But today, diseases hitch a ride on the air travel network, so where the disease spreads fastest has little to do with physical geography. What Dirk figured out though is that geography is just another sort of network. If we arrange the airline network in the right way, with the origin of an epidemic at the center, we will again see the contagion spreading out like ripples in a pond. Check out this article in The Atlantic explaining the research.