RT Journal Article SR Electronic T1 Deploying dengue-suppressing Wolbachia: robust models predict slow but effective spatial spread in Aedes aegypti JF bioRxiv FD Cold Spring Harbor Laboratory SP 093229 DO 10.1101/093229 A1 Michael Turelli A1 Nicholas H. Barton YR 2016 UL http://biorxiv.org/content/early/2016/12/11/093229.abstract AB A novel strategy for controlling the spread of arboviral diseases such as dengue, Zika and chikungunya is to transform mosquito populations with virus-suppressing Wolbachia. In general, Wolbachia transinfected into mosquitoes induce fitness costs through lower viability or fecundity. These maternally inherited bacteria also produce a frequency-dependent advantage for infected females by inducing cytoplasmic incompatibility (CI), which kills the embryos produced by uninfected females mated to infected males. These competing effects, a frequency-dependent advantage and frequency-independent costs, produce bistable Wolbachia frequency dynamics. Above a threshold frequency, denoted p̂, CI drives fitness-decreasing Wolbachia transinfections through local populations; but below p̂, infection frequencies tend to decline to zero. If p̂ is not too high, CI also drives spatial spread once infections become established over sufficiently large areas. We illustrate how simple models provide testable predictions concerning the spatial and temporal dynamics of Wolbachia introductions, focusing on rate of spatial spread, the shape of spreading waves, and the conditions for initiating spread from local introductions. First, we describe data from Aedes aegypti populations near Cairns, Australia that demonstrate longdistance dispersal and provide an approximate lower bound on p̂ for wMel in northeastern Australia. Second, we use approximations for p̂ and dispersal distances to predict the outcome of 2013 releases of wMel-infected Aedes aegypti in Cairns, Australia, using idealized diffusion models of temporal and spatial dynamics. Third, we consider the robustness of diffusion-based predictions to incorporating two important features of wMel-Aedes aegypti biology that may be inconsistent with the diffusion approximations, namely fast local dynamics induced by complete CI (i.e., all embryos produced from incompatible crosses die) and long-tailed, non-Gaussian dispersal. With complete CI, long-tailed dispersal changes wave-width predictions only slightly; but it can significantly reduce wave speed relative to the diffusion prediction; it also allows smaller local introductions to initiate spatial spread. Finally, we apply our analyses to produce operational guidelines for efficient transformation of vector populations over large areas. We demonstrate that even very slow spatial spread, on the order of 10-20 m/month (as predicted), can produce area-wide population transformation within a few years following initial releases covering about 20-30% of the target area.