Malaria is a difficult thing to stop, the local population needs to work in concert to stop mosquitoes in the area.
It is difficult for people from underdeveloped countries to work towards long term goals, they want instant gratification.
If they kill mosquitoes, they want to see dead mosquitoes and many.
The idea of sleeping under a mosquito net is often bewildering, they do realize the immediate danger of one mosquito bite. There is not instant feedback, not gratification by stopping the mosquitoes, except for personal comfort.