Scaled deployment of Wolbachia to protect the community from dengue and other Aedes transmitted arboviruses

Abstract

Background: A number of new technologies are under development for the control of mosquito transmitted viruses, such as dengue, chikungunya and Zika that all require the release of modified mosquitoes into the environment. None of these technologies has been able to demonstrate evidence that they can be implemented at a scale beyond small pilots. Here we report the first successful citywide scaled deployment of Wolbachia in the northern Australian city of Townsville. Methods: The wMel strain of Wolbachia was backcrossed into a local Aedes aegypti genotype and mass reared mosquitoes were deployed as eggs using mosquito release containers (MRCs). In initial stages these releases were undertaken by program staff but in later stages this was replaced by direct community release including the development of a school program that saw children undertake releases. Mosquito monitoring was undertaken with Biogents Sentinel (BGS) traps and individual mosquitoes were screened for the presence of Wolbachia with a Taqman qPCR or LAMP diagnostic assay. Dengue case notifications from Queensland Health Communicable Disease Branch were used to track dengue cases in the city before and after release. Results: Wolbachia was successfully established into local Ae. aegypti mosquitoes across 66 km 2 in four stages over 28 months with full community support. A feature of the program was the development of a scaled approach to community engagement. Wolbachia frequencies have remained stable since deployment and to date no local dengue transmission has been confirmed in any area of Townsville after Wolbachia has established, despite local transmission events every year for the prior 13 years and an epidemiological context of increasing imported cases. Conclusion: Deployment of Wolbachia into Ae. aegypti populations can be readily scaled to areas of ~60km 2 quickly and cost effectively and appears in this context to be effective at stopping local dengue transmission

A genomic approach to inferring kinship reveals limited intergenerational dispersal in the yellow fever mosquito

“…These interventions aim to replace uninfected Ae. aegypti with Wolbachia ‐infected mosquitoes that have a reduced potential to transmit dengue (Hoffmann et al, ; O'Neill et al, ; Schmidt, Barton, et al, ). The long‐term persistence and spread of Wolbachia in Ae.…”

An elusive endosymbiont: DoesWolbachiaoccur naturally inAedes aegypti?

“…aegypti with novel Wolbachia infections has been achieved in several countries , Garcia et al, 2019, Nazni et al, 2019. Following releases in Australia and Malaysia, Wolbachia infections have maintained a stable, high frequency in most locations, coinciding with reduced local dengue transmission (O'Neill et al, 2018, Ryan et al, 2019, Nazni et al, 2019. Population suppression can be achieved through male-only releases of Wolbachiainfected males, resulting in cytoplasmic incompatibility with wild females.…”

A genomic approach to inferring kinship reveals limited intergenerational dispersal in the yellow fever mosquito

“…These interventions aim to replace uninfected Ae. aegypti with Wolbachia-infected mosquitoes that have a reduced potential to transmit dengue (Hoffmann et al, 2011;O'Neill et al, 2018;Schmidt, Barton, et al, 2017). The long-term persistence and spread of Wolbachia in Ae.…”