Malaria mosquitoes usually bite from twilight to sunrise. The dengue fever and Japanese encephalitis-transmitting mosquito bite day and night, whereas the yellow fever-transmitting mosquito tends to bite during the day.
In areas where there is a risk of contracting these diseases wearing clothing covering arms and legs and using mosquito spray on non covered skin (face, neck, hands and ankles). If you sleep in non air-conditioned rooms you should always use a mosquito net impregnated with mosquito repellent.
The mosquito net must be tight and as big enough to tuck it under the mattress or another mat when you go to sleep. Remember to tuck the net under the mattress during the day to prevent the mosquitoes from entering into your bedding when it is not being used.