Researchers in Brazil use mosquitoes as Trojan horses against dengue

Brazilian researchers announced this Wednesday that they have launched a method to fight against mosquito transmitter dengue that uses the same insect as a Trojan horse to spread a larvicide, in the midst of the worst epidemic of this disease in the history of the country.

It is a technique developed by the public laboratory Instituto Fiocruz and consists of a container filled with water in which they place a cloth impregnated with larvicide that, although it does not kill the mosquitoes, kills the larvae in the breeding sites.

“Attracted by the water and the black color of the container, the insect comes to the station and becomes contaminated with a larvicide that it spreads everywhere. “Who better to find breeding sites than the mosquito itself?”says Professor Rodrigo Gurgel, coordinator of the laboratory at the University of Brasilia, responsible for this project.

Brasilia is the city that has the highest rate of infections in the historic epidemic that Brazil is experiencing this year and one of the most affected regions in the capital is the Structural City, a poor area built around a landfill, where a large part of the population It does not have basic sanitation.

Year after year, neighbors like Manoel dos Santos face an increase in dengue cases during the rainy season.

“On this street, the majority have already passed dengue. My neighbor and several other people. There are few people who have not had it”explains Santos.

In 2020, researchers from the University of Brasilia undertook a project, funded by the World Health Organization (WHO), to install larvicide stations and tubes to collect and analyze mosquitoes in 150 houses in this neighborhood, to which they returned for 11 years. following months for follow-up.

Although they are still analyzing the results, Professor Gurgel thinks that “they will be able to control the mosquito” with the same effectiveness as another study they carried out in 2017 in the São Sebastião region, also located in Brasilia, where a 66% the presence of mosquitoes.

In fact, some residents of the Structural City, like Reginaldo Lima, claim to have noticed an improvement since the installation of these stations.

“After they started this process, the situation improved a lot. Before there were many mosquitoes and we couldn’t sleep at night”declares Lima.

As Gurgel explains, “Its advantage over other technologies, such as genetically modified mosquitoes, is that there is no need for large laboratories. Any health service can produce a bottle like this at very low cost.”

Given its effectiveness, the Ministry of Health recommended its use in Brazilian municipalities to control the population of the Aedes aegypti species and it has already been implemented in cities in five states.

At the beginning of April, Brazil recorded a new annual record of deaths from dengue, with 1,116 deaths in the first fourteen weeks of the year, exceeding the total of 1,116 deaths that occurred in all of 2023.

For Gurgel, climate change is one of the obvious causes of this situation.

“The higher the temperature, the faster mosquitoes develop and the more rain, the more breeding sites. “In recent years, we have seen a clear increase in temperature and a change in precipitation cycles.”says Gurgel.

On the other hand, it also points to the lack of control work by the health system throughout the year and the lack of awareness among the population.

According to the professor, “he 75% of breeding sites are located inside homes, which means that if residents were more careful with their homes, many breeding sites would likely be eliminated.”

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