Nature Commun. (in the press); preprint at http://arxiv.org/abs/1408.1168 (2015)

The Black Death spread across Europe leaving few in its wake, so it's natural to think about it as a wave of devastation. But spare a thought for how it might have travelled, had the afflicted been able to hop on an airplane: long-distance flights foster the appearance of clusters in the spatial evolution of a contagion, with potentially more disastrous consequences. And now, Dane Taylor and colleagues have used a well-known model to map contagions in space, showcasing a technique for predicting — and perhaps controlling — spreading on complex networks.

Many networks are connected by spatially constrained edges (like roads on a map, for example), but may also incorporate additional edges connecting distant nodes. Taylor et al. cast these long-range connections as a source of noise in an otherwise geometric network, and observed two competing phenomena: wavefront propagation on the underlying geometric network, and the formation of clusters due to the noisy edges. Within their model, the team found regimes in which the spreading was almost unaffected by the noise edges — hinting at a possible means of contagion control.