Malaria is a serious, sometimes fatal, disease caused by a parasite.
Persons living in, and travelers to, any area of the world where malaria is transmitted may become infected. Malaria occurs in over 100 countries and territories. More than 40 percent of the people in the world are at risk. The World Health Organization estimates that yearly 300-500 million cases of malaria occur and more than 1 million people die of malaria. About 1,200 cases of malaria are diagnosed in the United States each year.