This study will collect blood samples for use in laboratory studies of malaria. The World Health Organization reports that 40 percent of the world's population is at risk for malaria, mostly in the poorest countries. It is a serious disease caused by parasites. Each year, 300-500 million infections lead to more than a million deaths. However, there are traits in red blood cells (erythrocyte) that protect people against malaria. In this study, polymorphism refers to the various kinds of red blood cell traits.