Heterogeneities in DENV transmission. The number of acute infections per activity space, Z_AS, was estimated for 257 index cases detected in Iquitos from 2008 to 2014. Histograms in (a) and (b) show Z_AS values across all clusters for DENV-2 and DENV-4, respectively. (c) Estimates of k, the dispersion parameter for a negative-binomial distribution, for each virus and the time of detection of an acute DENV infection (Dt) in a different person in the same activity space. (d) Estimates of k as a function of Dt for symptomatic and inapparent infections. All data points, with the exception of those with * had their parameter k being higher than unity (Table S2).