Doctors Without Borders (MSF) completed an innovative three-year project in Honduras, releasing more than 8 million mosquitoes infected with Wolbachia bacteria in the suburb of El Manchén, in Tegucigalpa. The project ensured that 97.8% of local mosquitoes carry this natural bacteria, which drastically reduces the transmission of dengue fever.
The sky over El Manchén is as blue as ever. In this suburb of Honduras’ capital, Tegucigalpa, the streets are full of people on their way to work and cars honk in heavy traffic. To the naked eye, this densely populated urban area looks nothing like it did two years ago. But a team from has been working hard for the past three years to make a microscopic change that could save lives.
Tests carried out in 2024, around a year after the project started, revealed that eight out of ten mosquitoes captured in El Manchén carried Wolbachia, a harmless bacteria present in more than 50 percent of insects. A year earlier, virtually none of the local mosquitoes carried this natural bacteria. AND El Manchén had, at that time, one of the highest dengue rates in the city. Currently, the prevalence of Wolbachia in the Aedes aegypti mosquito population in El Manchén is 97.8 percent.
This is important because the Wolbachia drastically reduces the likelihood of mosquitoes transmitting diseases like dengue feverwhich is potentially fatal and affects between 100 million and 400 million people worldwide every year.
The MSF team involved in the had released, since mid-2023, more than eight million mosquitoes deliberately infected with the Wolbachia bacteria in the suburb of El Manchén – the purpose was that these mosquitoes to thrive, reproduce and transmit Wolbachia through generations, drastically reducing the incidence of dengue in the region.
This innovative initiative combined science and community participation to reduce disease transmission. Almost three years later, the mosquito project has concluded with promising results and researchers are buzzing with excitement.
Analyze final scientific results
With prevention project activities in the suburbs of Tegucigalpa having ceased in September 2025, the time is now to analyze the final scientific results, with the study’s conclusions expected to be published in the first quarter of 2026. At the same time, MSF teams continue to carry out epidemiological monitoring of dengue and other arbovirus diseases in the region.
“This project shows that innovation and community participation can go hand in hand to respond to diseases that are transmitted by vectors”, highlights the coordinator of this MSF project, Edgard Boquín. “It was a unique project within MSF globally, which has provided us with valuable lessons in prevention and public health.”
The result of a collaboration with the Honduran Ministry of Health, the National Autonomous University of Honduras, the World Mosquito Program, the Central District Metropolitan Health Region and local communitiesthe Arbovirus Prevention Project in Tegucigalpa focused on the neighborhoods of La Joya, El Edén and El Manchén. And, in all phases of the activities of this prevention project, there was strong participation from the communities.
In addition to the use of mosquitoes carrying the Wolbachia bacteria, other vector control methods were also carried out, such as spraying the interior of houses and applying pyriproxyfen discs to water wells. In La Joya and El Edén, more than 7,500 homes were sprayed and treated for well water.
“It was true teamwork”, points out Edgard Boquín. “This is the first time that MSF and the Global Mosquito Program have worked together to prevent arboviruses like dengue. Our strength in community engagement and the technical expertise of the World Mosquito Program Mosquitoes complemented each other to make this a reality.”
The project coordinator recalls that “As mosquitoes were released, there were more and more mosquitoes in this area, which caused some distress to local communities.” “And when a new dengue outbreak broke out in the capital [no ano passado]it became more difficult to approach people to tell them about dengue. But by involving them directly in the activities, we were able to do everything we had planned.”
Early statistical analyzes suggest that the introduction of Wolbachia even contributed significantly to reducing the incidence of dengue in El Manchén during that outbreak. Cases of the disease were noticeably lower than what had occurred in historical comparison trends between this suburb and other areas that did not receive mosquitoes carrying the bacteria.
“The Wolbachia method will be a very positive tool to reduce dengue in Honduras. We have seen for a long time how much people have suffered with dengue, but we are already hearing positive stories from communities that something is changing after Wolbachia was released. This gives hope to people who have had dengue or have seen someone close to them get sick”, says Edgard Boquín.
