Scientists in Brazil announced the start of experiments with an “innocuous, self-sustainable” method to fight transmission of the dengue virus by the Aedes aegypti mosquito, using a bacterium that is naturally occurring in nature.
“We are looking at the possibility of a control method that has a challenging objective: reducing and even eliminating dengue,” Paulo Gadelha, president of the state-run Oswaldo Cruz Foundation (Fiocruz), told the press during a recess in the 18th International Congress on Tropical Medicine and Malaria, running Sunday Sept. 23 to Thursday Sept. 27 in Rio de Janeiro.
Gadelha made the announcement Monday sitting alongside Scott O’Neill, head of the “Eliminate Dengue, Our Challenge” programme led by Monash University of Australia and financed by Fiocruz and the U.S. Foundation for the National Institutes of Health.
The strategy, already approved in Australia, Vietnam and Indonesia, will now be tested in Brazil, as soon as the health and environment agencies give their authorisation.
“This is an important method, because it could become one of the most promising weapons to fight dengue in a natural and sustainable manner, and it poses no risk to the human population or to nature,” Gadelha told IPS after the news briefing.
The technique is based on Wolbachia pipientis, an intracellular bacterium that naturally occurs in more than 70 percent of all insects, such as the fruit fly, butterflies, dragonflies, and several species of mosquito.
But Wolbachia cannot infect affect humans or other vertebrates.
O’Neill and Fiocruz scientist Luciano Moreira explained that after years of research, lab tests showed that when the bacterium is introduced in the Aedes aegypti mosquito, it acts as a vaccine, making the insect resistant to the virus that causes dengue fever – and thus keeping it from spreading the virus to people.
“After thousands of attempts over the space of a number of years, in Australia they managed to infect the eggs of the Aedes aegypti with the bacterium, through microinjections. Afterwards, the bacteria were found in the tissue of the mosquitoes,” Moreira said.
The method is based on the scheduled release of Aedes aegypti mosquitoes infected with Wolbachia which, when they breed with local mosquitoes, pass the bacteria on to the next generation through their eggs.
The idea is for most of the local mosquito population to gradually be infected with Wolbachia, and thus become incapable of spreading dengue, the researchers explained in a Fiocruz statement.