Brazil to expand use of wolbachia bacteria against dengue fever

In July of this year, the first releases of Aedes aegypti mosquitoes infected with the wolbachia bacteria will commence in six municipalities across different states: Uberlândia in Minas Gerais; Londrina and Foz do Iguaçu in Paraná; Presidente Prudente in São Paulo; Joinville in Santa Catarina; and Natal, the capital of Rio Grande do Norte. The strategy will expand next year to 22 additional municipalities in Minas Gerais.

The Ministry of Health reports that Brazil is the pioneering nation to adopt this technology as a public policy initiative aimed at curbing dengue cases over the medium and long term.

The Wolbachia method involves introducing the bacterium into mosquito eggs in a laboratory setting, thereby producing Aedes aegypti mosquitoes that harbor the microorganism. These infected mosquitoes are incapable of transmitting viruses responsible for diseases such as dengue, Zika, Chikungunya, or yellow fever. As they reproduce, they pass on the bacteria to subsequent generations, leading to a reduction in disease transmission from mosquitoes to humans.

Prior to the release of mosquitoes, the local population is informed about the anticipated increase in mosquito numbers in the area. Ethel Maciel, Secretary for Health and Environmental Surveillance at the Ministry of Health, clarifies that insecticide application is prohibited in areas where mosquitoes are released. This is because the method focuses on altering the mosquito population by introducing wolbachia-infected mosquitoes to replace those that are not infected.

Maciel explains that several criteria must be met for a municipality to qualify for this strategy, with one key factor being minimal temperature fluctuations during the day, as these fluctuations hinder the adaptation to mosquitoes infected with the wolbachia bacteria.

Effectiveness

According to the secretary, the strategy has proved to be very effective. One example is Niterói, situated in the state of Rio, which was the pioneering city to implement the project during its research phase in 2014. Niterói witnessed a remarkable decrease in dengue cases by 69.4 percent, Chikungunya cases by 56.3 percent, and Zika cases by 37 percent. Comparatively, the incidence of these diseases in neighboring municipalities remains substantially higher, underscoring the significant potential of this strategy in the medium and long term," emphasized the secretary during an interview this week.

Other cities across the country adopting the Wolbachia method include Campo Grande in Rio de Janeiro and Petrolina in Pernambuco. Beyond Brazil's borders, Indonesia, along with three other nations, collaborates in the research initiative alongside the World Mosquito Program.

On Monday (29), the Ministry of Health and the government of Minas Gerais jointly inaugurated the Wolbachia Biofactory in Belo Horizonte, the state capital. Operated by the Oswaldo Cruz Foundation (Fiocruz), this facility marks a significant step forward for Brazil, enhancing its capability to produce one of the foremost technologies in combating dengue and other arboviruses.