One of the species of mosquito that causes yellow fever, and dengue fever is known as Aedes aegypti.
Specifically, it’s the females of that species that transmit the pathogen and diseases.
It’s common sense to understand that if you can reduce the female population of the aedes aegypti species, you can automatically reduce the spread and the death toll caused by the pathogens and diseases those female mosquitoes transmit.
That’s exactly what Bill Gates did.
His firm, Oxitec, raises millions of male aedes aegypti mosquitoes and then manipulate their genes.
After the manipulation, the firm releases the genetically modified males aedes aegypti mosquitoes into the environment.
These modified male mosquitoes mate with the wild female ones and pass on a “corrupt” gene that kills female mosquitoes in the larval stage.
That way, the population of female aedes aegypti mosquitoes reduces and then yellow fever and dengue fever automatically reduces too since it’s the females that transmit diseases.
In Brazil, Malaysia, Panama and the Cayman Islands, millions of genetically modified mosquitoes were released into the environment and they have successfully been used to drastically reduce yellow fever, malaria and dengue fever related disease and death.