Facilitating W olbachia invasions

Following the recent transfer of W olbachia from D rosophila to A edes aegypti mosquitoes, the w M el W olbachia infection now has been introduced successfully into natural A . aegypti populations in northern Q ueensland with likely suppressive effects on the transmission of dengue and other arboviruses. However, the introduction of other W olbachia strains that might affect the population dynamics of A . aegypti and/or provide almost complete blockage of virus transmission like w M el P op remains challenging given the strong fitness costs of these strains for their hosts. Here, the different approaches that might be followed in facilitating introductions of such strains, including ways to suppress populations prior to release stains, interventions during release to boost the fitness of released strains and timing of releases to provide an initial boost in infection frequencies are reviewed. Suppression of a single mosquito life stage prior to release is likely to have little impact on invasion success, whereas suppression of populations of uninfected mosquitoes at all life stages provides a promising strategy for invasion. Implementation of these approaches requires a detailed understanding of the local ecology of mosquito populations, as well as an understanding of the level of isolation of a local population, particularly when the W olbachia infection results in population suppression as well as strong blockage of virus transmission.