In August last year, leading scientific journal Nature published two papers by Eliminate Dengue Program members that described the results from our work in the lab and thefirst open field trials of the Wolbachia method conducted in far north Queensland in 2011.
This first field trial involved releasing Wolbachia mosquitoes every week for 10 weeks. Five weeks after the final release it was determined that 100% of the mosquitoes at Yorkeys Knob carried Wolbachia and 90% in Gordonvale.
Ongoing monitoring (to February 2012) tells us that Wolbachia is still present in 99% of Aedes aegypti mosquitoes in Yorkeys Knob and Gordonvale.
With the help of residents in neighbouring Holloways Beach and Pyramid Estate we are also monitoring mosquito populations in these suburbs to see if Wolbachia is spreading beyond the trial sites. We have detected a very small number of mosquitoes with Wolbachia here and will continue monitoring in these suburbs and at Yorkeys Knob and Gordonvale over the 2012 wet season.
The 2011 published results recorded many years of work and provided the first 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. But we still have a lot of work to do. Final proof on the ability of Wolbachia to reduce dengue disease in communities will not be determined until field trials in dengueendemic countries are completed. Planning for these is underway in Vietnam, Indonesia and Brazil. This is needed because there is not sufficient dengue transmission in Cairns to get enough data to accurately measure thedisease impact.
At the same time, due to the overwhelming success of the 2011 trial, we had a rethink of our strategy for a second trial in Australia in 2012 for what we believe will be an even better outcome for long-term dengue-prevention in Cairns and inform the roll-out of the Wolbachia method internationally.
Diagram below: Wolbachia dengue control method Mosquitoes infected with Wolbachia mate with wild mosquitoes, and pass Wolbachia to their offspring. If all Aedes aegypti mosquitoes have Wolbachia they will have reduced ability to transmit the denguevirus between people.