Unleash the Mosquitoes

Genetically engineered, bacteria-infected and sterilized mosquitoes are among the cutting-edge weapons being tested against diseases like Zika and dengue, even as some experts say old-fashioned tools like DDT may be worth discussing. 

Every weekday at 7 a.m., a van drives slowly through the southeastern Brazilian city of Piracicaba carrying a precious cargo — mosquitoes. More than 100,000 of them are dumped from plastic containers out the van’s window, and they fly off to find mates. But these are not ordinary mosquitoes. They have been genetically engineered to pass a lethal gene to their offspring, which die before they can reach adulthood. In small tests, this approach has lowered mosquito populations by 80 percent or more.