Laos Dengue Cases Drop 92% With Bacteria-Carrying Mosquitoes

Sengsouly Phaiboun still remembers when her brother's friend died from dengue fever after going to the hospital for treatment. In 2024, Laos recorded 20,000 dengue cases and 11 deaths from the mosquito-borne disease that causes high fever, joint pain, and muscle aches.

Two years earlier, Save the Children Laos and the World Mosquito Project launched an innovative solution. They started breeding mosquitoes carrying Wolbachia bacteria, which makes them immune to dengue and other viruses.

The strategy sounds simple but works brilliantly. Scientists release these safe mosquitoes into communities where they mate with infected ones. Their offspring carry the Wolbachia gene, gradually replacing dangerous mosquito populations with harmless ones.

The project specifically targets low-income areas where dengue hits hardest. Poor neighborhoods often have standing water, open eaves, and inadequate drainage that create perfect breeding grounds for mosquitoes. Residents there also have less access to healthcare and prevention education.

Sathaphon Phoumarinno, who leads the initiative at Save the Children Laos, explained that healthier communities mean fewer medical expenses and more people able to work and attend school. The project trains local volunteers to identify hotspots and educate neighbors about prevention.

The results speak for themselves. Between 2025 and mid-2026, Laos recorded only 1,500 dengue cases nationwide compared to 20,000 in 2024. That's a 92.5% drop in roughly two years.

The program reached more than 1.5 million people across and beyond the capital city of Vientiane. Community members gave it a 99% acceptance rating in 2023, showing strong local support.

The Ripple Effect

This year, the project expanded into four new provinces: Oudomxay, Luang Prabang, Savannakhet, and Champasak. The expansion aims to protect 1.2 million more people, including communities in northern Laos where 41% of the country's poorest residents live despite making up less than 30% of the population.

Unlike temporary emergency responses, this solution keeps working after just one mosquito release. The Wolbachia gene passes naturally from generation to generation without harming the ecosystem or requiring ongoing intervention.

The approach has already succeeded in Brazil, Peru, and Colombia. In Laos, it received backing from the Australian Government and the country's own health ministries, showing how international cooperation can tackle diseases that disproportionately affect vulnerable populations.

For a country where the average annual income sits at just $2,000, reducing healthcare costs matters tremendously. Families no longer face the choice between medical treatment and other basic needs.

"For community members, I believe DDDiL means hope for a future with fewer dengue cases, healthier and happier communities," Phoumarinno said, and the numbers prove him right.