Our goal
Our research program is developing an innovative biological approach to manipulate mosquito populations to make them incapable of transmitting dengue viruses between people. If successful it will greatly reduce our reliance on conventional insecticide-based mosquito control.
Our approach
The approach is centered on a naturally occurring bacterial agent known as Wolbachia pipientis.This bacterium is estimated to occur naturally in up to 70% of all insect species. Considering that scientists estimate there may be more than 5 million different insect species on the planet, Wolbachia is extremely common in the environment. We know that in addition to well-known insects like Birdwing butterflies, Wolbachia also occurs naturally in many mosquito species that bite humans. Interestingly it does not occur naturally in the mosquito species that are known to be of major importance in spreading human diseases like malaria and dengue between people.
Our research program is investigating whether we can use Wolbachia strains that occur naturally in insects to influence the ability of the mosquito Aedes aegypti to transmit dengue viruses between people.
Our findings
We have demonstrated that we can transfer Wolbachia from the fruit fly into the Aedes aegypti mosquito. We have also demonstrated that when Wolbachia is present in the mosquito it reduces the ability of the mosquito to support and transmit dengue viruses. We have also shown that Wolbachia infections in mosquitoes reduce the ability of mosquitoes to transmit other human pathogens that cause malaria, chikungunya and yellow fever.
In August 2011 leading scientific journal Nature published two papers that describe the successful results from the first field trials of the Wolbachia method in Australia. These results provide the first successful example where wild insect populations have been deliberately subject to an intervention that seeks to change the mosquitoes’ ability to transmit viruses that cause disease. These findings also provide evidence that Wolbachia-based strategies can be deployed as a practical approach to dengue suppression with the potential for area-wide implementation at low cost.
Current work
Field trials are continuing in Australia that are examining the ability of different Wolbachia strains with stronger dengue interference properties to establish in wild mosquito populations.
In addition to developing the Wolbachia method in Australia we are also working with local scientists and field sites in Vietnam, Indonesia, Brazil and Thailand. Trials are being designed in these locations that will directly test the impact the approach has on reducing dengue disease in communities.
If successful we hope the Wolbachia method of control will make a significant contribution to reducing the risk of acquiring dengue for the estimated 2.5 billion people that currently live in dengue transmission areas.
The Wolbachia approach is fully compatible with other methods of control such as the application of residual insecticides and may augment future methods of control such as dengue vaccines currently being developed.