Against Dengue, Brazil will use millions of mosquitoes modified by the Wolbachia bacterium

Against theepidemic Of Dengue The Brazil has decided to take the hard way: in the next few weeks 6 cities of the South American state will release millions of mosquitoes modified in the laboratory. The insects will become infected by the Wolbachia bacterium, which is not harmful to humans. Brazil aims to create a containment campaign by activating a process of cytoplasmic incompatibility with the aim of putting a stop to the almost 2 million infections from Dengue.

What is cytoplasmic incompatibility

The release of infected mosquitoes comes alongside the more traditional disinfestations and appeals to the population to use repellents, mosquito nets, covering clothing and to avoid water stagnation in saucers. All useful measures, but insufficient in a state like Brazil, where rain alternates with long periods of heat, thus creating ideal conditions for the proliferation of mosquitoes.

The health authorities have therefore decided to resort to the trick of cytoplasmic incompatibility: in short, not being able to sterilize the Aedes Aegypti mosquitoes that live in nature, we will aim to make them pair with mosquitoes whose reproductive capacity has been altered in the laboratory. According to plan, the embryos born from these matings will not be able to develop correctly and they will die before reaching adulthood. Given the short life cycle of mosquitoes, the strategy of this project could have decisive effects and act as an input for other similar interventions in other South American countries plagued by Dengue.

Other similar interventions

This is nothing new, to be honest: the idea was developed within the World Mosquito Program and has already been applied in several countries, including Australia, Mexico, Colombia And Honduras. The project was started in the past years also in Brazilbut without giving it continuity: a first experiment was started in 2015 Niteroi, a city of half a million inhabitants on Guanabara Bay near Rio de Janeiro. Niterói had thus become the first city with complete coverage of Wolbachia, which contributed to keeping the spread of Dengue in the district low for a certain period. But the intervention, which was not repeated over time and was limited to a single city, was not enough to achieve decisive results and the state of Rio officially declared a Dengue emergency last month.

According to scientists, by continuing with the Wolbachia program in order to block dengue infections, within 10 years approximately 70 million Brazilians in various cities will be able to be protected.

Bacterium Wolbachia, what is it?

Wolbachia belong to a genus of Gram-negative intracellular parasitic bacteria that infect various species of arthropods, including many insects. Organisms infected by the Wolbachia bacterium respond by reporting alterations to reproductive capacity, including the cytoplasmic incompatibility on which the Brazilian health authorities are focusing.

Dengue vaccine

In the meantime, the Dengue vaccine. News that hit the front pages, following the spread of some cases of Dengue in Italy. At the moment the diffusion of the vaccine in Italian hospitals is happening in a patchy manner. Matteo Bassetti, director of the Infectious Diseases department at the San Martino Polyclinic in Genoa, explains that vaccination is recommended for “those who have already had a first infection, but also for those who travel to endemic areas where they stay for a long time”. In summary, “if one goes for a week’s holiday in Rio de Janeiro I would not recommend vaccination for Dengue, but if one goes to work permanently in Brazil or Argentina in this period, yes”.