Important update
After 3 years, the 'Applying Wolbachia to Eliminate Dengue' Randomised Controlled Trial conducted in Yogyakarta City shows incidence of dengue cases in intervention areas decreased by 77% compared with untreated areas within the study site.
The World Mosquito Program is working in and around Yogyakarta to protect communities from mosquito-borne diseases like dengue, Zika, chikungunya and yellow fever.
Following encouraging results from our initial trials in Sleman and Bantul Districts in 2014, a large-scale efficacy study to evaluate the impact of our Wolbachia method on dengue transmission is now underway in Yogyakarta City. The project is working closely with government, health authorities and local communities to undertake this work, which includes a quasi-experimental study and the first randomised controlled trial of Wolbachia for dengue control.


Before our project started, there were regular large outbreaks of dengue in this area. The aim of these releases was to establish Wolbachia in the local mosquito populations to reduce the transmission of mosquito-borne diseases. Wolbachia mosquito releases within Yogyakarta City began after two years of engagement with communities and approval by the provincial government.
In the first phase of the Yogyakarta City deployments, the team introduced mosquitoes with Wolbachia into seven urban villages on the northwest perimeter of Yogyakarta City.
The impact on disease is being evaluated by comparing dengue case notifications to the District Health Office from the Wolbachia-treated communities with a pre-defined untreated control area, in what is known as a quasi-experimental study design.
After 24 months of Wolbachia establishment in the intervention area in Yogyakarta City, the incidence of identified dengue cases in the intervention area has decreased by 73 per cent in comparison to the control area.
A randomised controlled trial of the Wolbachia method commenced in Yogyakarta City in 2017 in order to rigorously evaluate the impact of Wolbachia on the transmission of dengue and other mosquito-borne diseases. Results announced in August 2020 showed a 77% reduction in dengue incidence in areas of the study site that were treated with Wolbachia. Welcome news for the people of Yogyakarta and a major breakthrough for the program.

Yogyakarta City
Following community engagement and education in 2016, we released Wolbachia-carrying mosquitoes in Yogyakarta City in 2016 and 2017. Public acceptance of the project prior to release of mosquitoes was 88 per cent.
The first releases in Yogyakarta City were in seven urban villages on the north-west perimeter in August 2016 to March 2017. We are currently monitoring the levels of Wolbachia in the mosquito population and collecting data on the incidence of dengue in this intervention area.
We also collect data on the incidence of dengue in a comparable control area on the south-west perimeter of the city, where Wolbachia has not been released and where dengue incidence has historically been very similar to the intervention area. Together this release area and comparable control area are known as the quasi-experimental study, because we are able to directly compare the effect of Wolbachia on the incidence of dengue.
After 24 months of Wolbachia establishment in the quasi-experimental release area, the incidence of dengue cases reported to the Yogyakarta District Health Office decreased by 73 per cent in the intervention area compared to the control area.

Sleman District
Following community engagement and education in 2012 and 2013, we released Wolbachia-carrying mosquitoes in Sleman District in 2014. Currently we’re monitoring the levels of Wolbachia in the mosquito population and collecting data on the incidence of dengue. In Sleman District, public acceptance of the project (prior to release of mosquitoes) was 95 per cent.
The community has been enthusiastically supporting the project in Sleman District, with more than 1850 volunteers helping to release mosquitoes, host bug traps and promote the project.

Bantul District
Following community engagement and education in 2014, we released Wolbachia-carrying mosquitoes in Bantul District in 2014 and 2015. Currently, we’re monitoring the levels of Wolbachia in the mosquito population and collecting data on the incidence of dengue. In Bantul District, public acceptance of the project (prior to release of mosquitoes) was 90 per cent.
The community has been enthusiastically supporting the project in Bantul District, with more than 1800 volunteers helping to release mosquitoes, host bug traps and promote the project.