This research project is investigating an innovative approach to manipulate mosquito populations to make them incapable of transmitting dengue viruses. We are targeting mosquito age, as it is one of the most sensitive factors influencing the spread of mosquito-transmitted diseases. As the incubation period of dengue virus within the mosquito is long relative to mosquito lifespan, only a small number of mosquitoes contribute to the transmission of dengue. Removing the older individuals in the mosquito population will interrupt dengue transmission to humans. By introducing naturally occurring life-shortening strains of Wolbachia endosymbionts into mosquito populations we can selectively remove old mosquitoes. Additionally, life-shortening Wolbachia strains have their own mechanism for spreading themselves into mosquito populations. This genetic drive mechanism, termed cytoplasmic incompatibility, has been well characterised in lab and field studies. Research suggests that a Wolbachia intervention strategy should be self-sustaining and may significantly reduce dengue transmission.
During the first five years of this research project we will complete four major research objectives in order to evaluate the feasibility of our proposed approach to controlling dengue.
Objective 1. We will generate strains of mosquitoes in the laboratory that carry life-shortening Wolbachia and better understand the mechanisms by which the bacteria cause life-shortening.
Objective 2. We will characterise the mosquito strains that carry these infections to determine the extent of life-shortening they generate, as well as their ability to spread into laboratory populations of mosquitoes. Laboratory studies will be followed by studies in contained field cages that determine how well the mosquito strains perform under field conditions.
Objective 3. We will collect baseline ecological data about Aedes mosquitoes in dengue transmission areas in Australia, Thailand and Vietnam. Results will be used in modelling studies that will be used to predict future effectiveness of the control method.
Objective 4. We will establish partnerships with communities and government/regulatory agencies to identify concerns relating to our proposed control method. This information will be used to direct our research efforts so that we are in a position to evaluate concerns about any future implementation of this control approach.
Successful completion of these objectives will enable us to determine if this novel approach to dengue control is scientifically achievable and socially acceptable. This project will not involve a release of mosquitoes containing life-shortening Wolbachia into the environment. Upon completion of this project we aim to have produced the necessary strains of mosquitoes containing life-shortening Wolbachia, collated the necessary ecological data to determined optimal release strategies, evaluated the social context surrounding potential release options and demonstrated the application of this method in securely enclosed field cages. Once this information is collected we hope to be in a position to determine if this control strategy should move to an implementation phase.