Brazil is taking an ambitious two-pronged approach to combat dengue, a mosquito-borne virus that kills thousands in South America each year and is spreading rapidly across the region. Health authorities are deploying billions of mosquitoes infected with Wolbachia bacteria while preparing to roll out a locally produced dengue vaccine.
Last month, vehicles traversed three Brazilian cities, releasing clouds of mosquitoes carrying Wolbachia, a bacterium that reduces the insects’ ability to transmit the dengue virus. The effort is part of the largest mosquito-breeding facility in the world, located in Curitiba, which produces 100 million mosquito eggs per week. Operated by Wolbito do Brasil, the initiative aims to protect 14 million Brazilians annually.
The strategy comes amid a worsening dengue crisis. In 2024, Brazil experienced its deadliest outbreak to date, with 6.6 million probable cases and over 6,300 deaths. Neighboring countries, including Argentina, Colombia, and Peru, also recorded record outbreaks, while dengue-related deaths across Latin America and the Caribbean exceeded 8,400. Globally, fatalities reached a record high of more than 12,000.
Brazil is complementing the Wolbachia program with a homegrown vaccine developed at the Butantan Institute in São Paulo. Preliminary results from a phase III trial involving over 16,000 volunteers showed the vaccine was 89% effective in people previously infected with dengue and 74% effective in dengue-naïve individuals. Unlike existing vaccines, the Butantan candidate is designed to protect against all four dengue virus serotypes. Health authorities hope to begin administering tens of millions of doses starting in 2026.
The Wolbachia method, developed by the World Mosquito Program at Monash University and adapted for Brazil by researcher Luciano Moreira, works by infecting mosquitoes to reduce virus transmission. When infected mosquitoes breed, Wolbachia spreads through local populations, gradually lowering dengue rates. Early trials in Brazil have shown promising results, with some areas reporting up to an 89% reduction in probable dengue cases.
Experts say Brazil’s dual approach—deploying Wolbachia-infected mosquitoes and a locally produced vaccine—offers a model for other countries facing growing dengue threats. “Invest in both,” says Annelies Wilder-Smith of the World Health Organization. “It’s a long-term investment, because dengue will not go away. It will just get worse.”
Nature reports that Brazil’s efforts highlight the potential for combining innovative vector control with vaccination to curb one of the world’s fastest-growing infectious diseases. With climate change, urbanization, and global travel contributing to the spread of dengue, the world will be watching whether Brazil’s strategy can turn the tide.
