Launched in July 2025, a Brazilian mosquito factory is expected to produce 100 million eggs a week from the mosquito Aedes aegypti. However, unlike wild A. aegypti, the main transmitter of dengue virus, those churned out by the factory carry a harmless Wolbachia bacterium that curbs the insects’ ability to spread viruses including dengue and Zika. The idea is to release the modified mosquitoes, which researchers call wolbitos, into cities in Brazil, where they will mate with their wild counterparts and the females will pass the bacterium on to their offspring, gradually converting the local population.

The wolbito strategy, which is being spearheaded by the non-profit World Mosquito Program (WMP), has already shown success in Colombia, Indonesia and at home: in the Brazilian city of Niterói in the southeast, dengue cases dropped by 69% in areas where Wolbachia-carrying mosquitoes were released, compared with areas where they weren’t. Brazil’s federal government has adopted the approach to fight dengue infections — which surged to a record 6.5 million confirmed cases in the country in 2024 — alongside other preventive measures such as vaccines.

Excerpt from Mariana Lenharo, This is the world’s largest ‘mosquito factory’: its goal is to stop dengue, Nature, Sept. 3, 2025