It's something of a trick question, because the mosquito doesn't kill from its bite. The real culprit is malaria, and Dengue, and yellow fever and all the others on the list.
The B&MG Foundation is well-positioned to make a difference in these stats. I've heard that something as simple as mosquito nets can save hundreds of thousands of lives.
But one has to wonder... The population of the tropical countries on the map is hardly decreasing, from all this death & destruction. If we were able to save a million people per year, what would that do to these countries' economies? Could they feed that many more mouths? Would rainforest deforestation have to increase? Would there be enough water in the Nile and the Amazon?