JUAZEIRO, Brazil — Under normal circumstances, Cicera Maria da Silva would be less than excited about a researcher intentionally releasing thousands of mosquitoes just outside her husband's corner grocery store.
Mosquitoes here are not just a ubiquitous annoyance; they spread deadly diseases, including dengue fever, which struck Da Silva's mother a year ago.
But that's why she's OK with the truck that passes through this poor corner of Brazil a few times a week and pours so many of the winged creatures into the hot streets. These genetically engineered members of the species Aedes aegypti have been created in a lab, and are aimed at wiping out their brethren.
"What my mom went through when she got dengue was really, really bad," Da Silva says. "Anything that can be done to fight that is worth trying."
The small, sun-scorched neighborhood of Itaberaba in this city in Bahia state is the leading testing ground for a controversial effort to combat dengue fever, the harrowing disease that kills 22,000 people a year worldwide. Scientists backed by the state government are releasing millions of the engineered mosquitoes into the wild with the goal of exterminating the species here — and, perhaps eventually, the entire country or world.
Dengue fever can range in severity from a flu-like condition to hemorrhagic fever to death, and while the goal of eliminating mosquitoes en masse isn't new — usually through insecticides, which also affect other species — the genetic engineering approach is.
Lab workers use a needle to inject altered DNA into female mosquitoes' eggs. When the modified Aedes aegypti males breed in the wild, the larvae produced by females die young, before they can go on to bite anyone.
In Itaberaba, 84% of mosquito larvae now carry the modified gene, which means they will die before maturing, according to workers at the Moscamed lab in Juazeiro, which uses a process developed at UC Irvine and the Oxitec company in London. Pleased with the results, the state government has approved expansion of the program to five neighborhoods.
Scientists in Brazil are waiting for permission to take the next step: the carpet bombing of an entire city, Jacobina, with the male zombie mosquitoes.