Ari Hoffmann (University of Melbourne)
Wolbachia releases for disease control: Replacement, suppression, and something in between

Ary Hoffmann presented an insightful presentation about the Wolbachia releases for disease control; replacement, suppression, and something in between. To jog some memories, Wolbachia is a common bacteria in insects and Wolbachia block some dengue virus strain transmission. Although it is common in insects, this bacteria isn’t present in A. aegypti mosquitoes. Therefore, Wolbachia needs to be induced in the A. aegypti mosquitoes. Mosquitoes with Wolbachia were first released in villages near Guangzhou, China. After the release there is a suppression in mosquitoes level. But then, when the releases stop, the mosquito comes back. This evidence was supported by another study in Malaysia confirming this. Mosquitoes with Wolbachia decreased dengue at all 6 release sites tested. On the other hand, there are also studies that found that Wolbachia blocks the dengue virus inside the mosquito. Despite his success the egg of the mosquitoes induced with Wolbachia is quite sensitive with the environment temperature. The abundance really depends on the place they were deployed. Thanks to innovations, the new induced mosquitoes with Wolbachia group (with new Wolbachia variant) are very adaptable. Keep in mind, to maintain the suppression success there are several things that need to be considered carefully, like the host background, Wolbachia variant, operational issues, environment, mosquito population, and disease pressure.

Katherine L. Anders (World Mosquito Program; Institute of Vector-borne Disease, Monash University)
Latest Evidence from the World Mosquito Program

Katherine L. Ander delivered a passionate and insightful presentation highlighting the latest evidence from the World Mosquito Program (WMP). She communicated the 50% of all insect species have Wolbachia and the way it is transmitted from female insects to her offspring through the eggs to provide long-term protection from dengue for communities. It is a safe method for humans, animals and the environment and can manipulate reproductive outcomes to favour its introgression into a population. The WMP is deployed in 11 countries reaching a population of 10 million people in the communities where this program is present. She strongly communicated the method has a scalable deployment, reproducible public health outcomes and is cost-effective in high burden cities. She detailed outcomes for countries and cities of deployment and analysed what they mean, with the example of Yogyakarta experiencing a 77% reduction in dengue incidence and 86% reduction in dengue hospitalisations. A parallel case-control study supported a causal association between Wolbachia deployments and reduced dengue. Interestingly, other diseases experienced a reduction also, Chikungunya 56% and Zika 37%. Katherine L. Anders highlighted how these statistics show that due to this method only needing to be released one, it protects a large number of people in a small area and is a sustainable and economically viable solution to dengue fever. There are evident challenges within this large project which include and are not limited to; balancing competing priorities for additional evidence vs programmatic implementation, industrialising mosquito production and supply chain, understanding generalisability of the Wolbachia methods across different ecological settings, reducing implementation costs and demonstrating cost effectiveness/cost benefit. However despite these challenges she closed her presentation to passionately communicate that this is an equitable solution, does not require long term behavioural and is self-sustaining and cost efficient.

Adi Utarini (World Mosquito Program Yogyakarta)
World Mosquito Program Yogyakarta updates: From research to a national evidence-based policy on dengue

At the national level, there have been a lot of programs created by the government since 1968 until now to defeat dengue. One of them is the Wolbachia program. But, this program has a long journey before it will be implemented nationally. As Adi Utarini mentioned in her engaging presentation about World Mosquito Program Yogyakarta (WMP) updates: From research to a national evidence-based policy on dengue, this program was started in 2011. The first 2 years there was a phase 1 with the preparation process ensuring the feasibility and the safety of the program. Starting with a multidisciplinary team, then capacity building, taking compliance toward regulation, the early community and stakeholder engagement, and laying low on media engagement is the first strategy. Continuing the journey with phase 2 in 2014, WMP released 4 hamlets, in 10,00 population with ethical approval. The mission of this phase is to strengthen the research team, problem solving, gain respect from the community, and early media engagement. After a sustainable intervention, the trend in the site of research is promising. And phase 3 the scale-up study was held. As the research gets larger the teams need the collective consent such a village consent Using the quasi experimental study. The result is also impressive. The reduction in the experiment area is 79% higher compared to the control area. Another result from the public randomization, there is a 77% reduction in dengue in Yogyakarta. 86.2% decreased in hospitalised patients. Spreading the wings, the Wolbachia program was implemented in Bantul and Sleman regency as well. Since that both regencies circling Yogyakarta city and research was started in 2021 in Sleman and 2022 in Bantul. Empowering the community, the result is promising and stable in both areas. After the success in Yogyakarta, Sleman and Bantul, this program needs to be spread out towards Indonesia. Several areas have been chosen for the next implementation and have been recognised by the minister of health. And with the support from the ministry, from several areas planned, there are 5 areas that will implement Wolbachia soon.