See which city released genetically modified mosquitoes to try to combat dengue

Photo: Flávio Carvalho/WMP Brasil/Fiocruz/Disclosure

The city of Rio de Janeiro began, this Tuesday (2), a new wave of releases of “wolbitos”, Aedes aegypti mosquitoes infected with the Wolbachia bacteria. The microorganism is used to combat arboviruses such as dengue, zika and chikungunya, as it prevents the development of viruses that cause these diseases within their main vector, Aedes aegypti.

This Tuesday, the release was made in the Caju neighborhood. Next week, wolbites will be released in the Center and on Paquetá Island. The idea is to release these three locations over 20 weeks, in partnership with the Municipal Health Department, to increase the population of these mosquitoes.

In the environment, females contaminated with Wolbachia mate with mosquitoes without the bacteria. The puppies from these crosses are born already infected with the bacteria and, therefore, without the ability to transmit the diseases. If everything goes well, over time, the wolbite population increases, reducing the population of arbovirus vectors, and eliminating the need for new releases.

“We will carry out these releases by the end of August and hope to first establish this population of mosquitoes in these three areas. Who knows, next year we will be able to assess a reduction in the transmission of cases of these diseases”, explains Diogo Chalegre, leader of Institutional Relations at the World Mosquito Program (WMP, or World Mosquito Program, in Portuguese) in Brazil.

The so-called Wolbachia method was initially implemented in Niterói, in 2014, where releases have already been carried out in all neighborhoods. Next, it was the turn of the city of Rio, which has already had wolbites released in 29 neighborhoods, and municipalities outside the state of Rio: Campo Grande, Belo Horizonte and Petrolina (PE).

“What we can say is that there was an average reduction of 38% in dengue cases, in the 29 neighborhoods of Rio where we have already worked”, says Chalegre.

WMP coordinates strategies involving Wolbachia in the country, in partnership with the Oswaldo Cruz Foundation (Fiocruz) and funding from the Ministry of Health. Currently, according to Chalegre, 40 million wolbite eggs are produced per month and 3.2 million people live in the areas where these mosquitoes were released.

However, a new biofactory began to be built in Curitiba, in March this year, to increase production capacity to 400 million eggs per month, starting in 2025. With the expansion of capacity, it is expected to intensify releases to new locations, benefiting up to 70 million people over the next ten years.

*With information from Agência Brasil