Brazil announced their plans to breed large quantities of genetically modified mosquitoes to combat dengue. Dengue affects about 50 to 100 million people in tropical and subtropical regions every year. About 500,000 Brazilians suffered from this disease this year alone.

Dengue fever is an infectious disease that causes muscle and joint pains, potentially deadly hemorrhagic fever, or dengue shock syndrome. It is caused by four different virus strains, with the mosquito species Aedes aegypti as their primary carrier. The lack of a dengue vaccine caused Brazilian researchers to focus on mosquito control in the hopes of reducing the number of these disease-carrying mosquitoes.

The Brazilian initiative aims to produce genetically modified male Aedes aegypti mosquitoes. When these males breed with normal female mosquitoes, their offspring will die before reaching adulthood, which the initiative’s participants say “should reduce the [mosquito] population.” Two mosquito-infested towns in the state of Bahia, Brazil served as the testing grounds for this project. “Using this technique,” the Brazilian ministry said, “we reduced the mosquito population by 90 percent in six months.” A factory in Bahia, which was inaugurated last Saturday, will serve as the production facility for the modified mosquitoes. About four million mosquitoes will be produced each week.