Opposite patterns of synchrony: in sympatric disease metapopulations, Science 286

Measles epidemics in UK cities, which were regular and highly synchronous before vaccination, are known to have become irregular and spatially uncor-related in the vaccine era. Whooping cough shows the reverse pattern, namely a shift from spatial incoherence and irregularity before vaccination to regular, synchronous epidemics afterward. Models show that these patterns can arise from disease-speciÞc responses to dynamical noise. This analysis has implica-tions for vaccination strategies and illustrates the power of comparative dy-namical studies of sympatric metapopulations. A central debate in ecology concerns the rela-tive importance of deterministic and stochastic processes in shaping the dynamics of popula-tions (1). This issue has become more complex since the recognition that patterns of population fluctuation are substantially influenced by spa-tial structure and synchrony (2). Progress ha