Every time a mosquito dies, the world becomes a better place.

Glenn Reynolds

From Wikipedia "Various species of mosquitoes are estimated to transmit various types of disease to more than 700 million people annually in Africa, South America, Central America, Mexico, Russia, and much of Asia, with millions of resultant deaths. At least two million people annually die of these diseases, and the morbidity rates are many times higher still."

Related: let's eliminate species of mosquitoes that bite humans.