There are already genetically modified mosquitos that could be used to eradicate malaria. However, as their use is based on their liberation in ecosystems, there are concerns on how will these mosquitos affect them. These concerns arise from the idea that ecosystem relations are unpredictable, and that they are very difficult to engineer. But difficult is not impossible, and with time we will learn how to engineer ecosystems. 

Some references: 

BBC Article on genetically modified mosquitos being released in Florida

The company behind the release of mosquitos in Florida

Position of WHO on genetically modified mosquitos

Spanish blog-post on genetically modified mosquitos

The Guardian article on the failed dutch rewilding experiment

New York Times article on the failed Biosphere experiments

Scientific article on repopulation of forests using flammable pines

Article with information on the governance, regulation, and public engagement on genetically modified mosquitos