From Eric Kvaalen
It isn't necessary to eliminate all mosquitoes to get rid of diseases like Zika, malaria and dengue (13 February, p 26). All that is needed is to reduce their numbers to the point that these diseases fail to get passed on at a sustainable rate. And we needn't worry about mosquito extinction. They can always be reintroduced to an area if desired.
Les Essarts-le-Roi, France
