Mosquito net. Mother and child preparing to sleep under a mosquito net. The fine mesh of the net is designed to prevent them from being bitten by mosquitos and possibly contracting malaria. The net has also been treated with insecticide. Malaria is caused by protozoan parasites that are transmitted by the bites of mosquitos. It causes periodic fevers and can kill. It affects millions of people in tropical and subtropical regions of the world. Photographed in Kenya.