Having worked for an Indian NGO for several years, in West Bengal, a low lying delta area, I know all about mosquitoes. But, like all other types of genetic engineering, scientists are trying to find technological solutions to social problems. The people who suffer from malaria and dengue fever are usually too poor to afford good protection (e.g. bed nets) or health care, or even mosquito repellent. If they had the money for a few basics we wouldn’t need GE mosquitoes.
Lots of concerns were raised a couple of days ago in a piece in the NY Times.