Population structure is critical to infectious disease transmission. As a result, theoretical and empirical contact networks models of infectious disease spread are increasingly providing valuable insights into wildlife epidemiology. Analysing an exceptionally detailed data set on contact structure within a high-density population of European badgers Meles meles, we show that a modular contact network produced by spatially structured stable social groups, lead to smaller epidemics, particularly for infections with intermediate transmissibility. The key advance is...