Malaria frequently is a deadly disease caused by a protozoan parasite and transmitted by the Anopheles mosquito. Wahlgren and Chen (2000) provide an update on global malaria trends. The resulting infection can lead to death in 5-35% of severe cases, with Africa experiencing about one million child deaths per year. About 400 million people suffer from the disease, and there are about 130 million new cases each year. Possible reasons for the increase include resistance of the disease to anti-malarial drugs, resistance of the mosquitoes to insecticides, and global warming that has enlarged areas of disease tranmission.
Reference
Wahlgren, Mats and Qijun Chen, 2000: Special focus on malaria. Nature 406 No. 6794 (July 27).