Inside a massive factory in the industrial district of Curitiba, Brazil, millions of Aedes aegypti mosquitoes are breeding in a climate-controlled room filled with mesh cages. Every week, the facility produces more than 80 million mosquito eggs.
At the heart of this effort is Luciano Moreira, a soft-spoken agricultural engineer and entomologist, who opened the factory in July as part of an effort to fight mosquito-borne illnesses in the country.
At the Curitiba facility, mosquitoes are infected with a bacterium called Wolbachia, which curbs the transmission of harmful human pathogens. Their offspring are being released in Brazilian cities to help to control dengue, a deadly viral disease transmitted mainly by A. aegypti.
Until recently, Wolbachia-carrying mosquitoes were released only as part of small-scale research projects. The new factory marks a shift towards nationwide adoption of the method after Brazil’s federal government recognized it as an official public-health measure to combat dengue and other mosquito-borne diseases. People credit Moreira for making the case.
“He has succeeded not only in carrying out the academic work, running experiments to demonstrate the model’s effectiveness, but also in convincing political decision-makers to implement the technology,” says Pedro Lagerblad de Oliveira, a molecular entomologist at Brazil’s Federal University of Rio de Janeiro. “This is a skill that not all scientists have.”
Moreira’s interest in mosquitoes started in the late 1990s, when he was a postdoctoral fellow in the laboratory of molecular entomologist Marcelo Jacobs-Lorena, then at Case Western Reserve University in Cleveland, Ohio. There, Moreira contributed to the development of the first mosquito genetically engineered to block malaria transmission.
Several years later, he joined the lab of entomologist Scott O’Neill at Monash University in Melbourne, Australia, as a visiting scholar. O’Neill’s team had managed to infect A. aegypti with Wolbachia, a relatively harmless bacterium that infects reproductive cells in many arthropod species. Moreira set out to test whether Wolbachia affected the insects’ ability to transmit human pathogens.
It did. Wolbachia-carrying mosquitoes were less likely to pick up dengue from blood containing the virus than were uninfected ones (L. A. Moreira et al. Cell 139, 1268–1278; 2009). Scientists don’t yet understand the mechanism, but the bacterium might be competing with the virus for resources or it could be stimulating the production of antiviral proteins. The researchers found that it had the same protective effect against other viruses as well.
O’Neill started field testing the mosquitoes in Australia, and Moreira returned to Brazil for a research position at the Oswaldo Cruz Foundation (Fiocruz) in Belo Horizonte, a scientific institute affiliated with the country’s health ministry. He assembled a small team to start tests in Brazil.
“Mosquitoes were first produced in a kind of artisanal way in a tiny, heated room, using pipettes and manual processes,” Moreira says. But convincing public-health authorities to release millions of mosquitoes into their cities was a tough sell.
... continue reading