Household scale Wolbachia release strategies for effective dengue control

Abstract

The release of Wolbachia-infected mosquitoes into Aedes aegypti infested areas is a promising strategy for localised eradication of dengue infection. Ae aegypti mosquitoes favour urban environments as breeding habitats, so are often found in and around houses. Therefore, it is likely that they will infect members of the households that they reside around. Since population groupings within households are small, stochastic effects become important. Despite this, little work has been carried out to investigate the outcome of releasing Wolbachia-infected mosquitoes at a household scale, either from an empirical and theoretical stand point. In previous work, we developed and analysed a stochastic (continuous time Markov chain) model for the invasion of Wolbachia-infected mosquitoes into a single household containing a population of wildtype mosquitoes. In the present study, we extend our framework to a connected community of households coupled by the movement of mosquitoes. We use numerical results obtained via Gillespie's stochastic simulation algorithm to investigate optimal strategies for the release of Wolbachia-infected mosquitoes carried out at either the community or the household scale. We find that household scale releases can facilitate rapid and successful invasion of the Wolbachia-infected mosquitoes into the household population and then into the wider community. We further explore the impact of regular household scale releases of Wolbachia-infected mosquitoes for a range of compositions for the release population, time intervals between releases and proportion of households participating in the releases. We find that a single release household can provide sufficient protection to the entire community of households if releases are carried out frequently for a number of years and a sufficient number of females are released on each occasion.