Our results suggest that, for typical connection strengths between communities, spatial heterogeneity has only a weak effect on outbreak size distributions, and on the risk of emergence per introduction. For example, if R0=1.4 or larger, any village connected to a large city by just ten commuters a day is, effectively, just a part of the city when considering the chances of emergence and the outbreak size distribution.

Kubiak, R., Arinaminpathy, N., & McLean, A. (2010). Insights into the Evolution and Emergence of a Novel Infectious Disease PLoS Computational Biology, 6 (9) DOI: 10.1371/journal.pcbi.1000947

(See also “Measles Week, Part II: Emerging Disease“)