Lewis Smith Lake (or Smith Lake) is located in North-Central Alabama about 20 miles northwest of Birmingham in state of Alabama (U.S.) counties of Cullman, Walker and Winston. The 300-foot high dam, completed in 1961 by Alabama Power Company, impounds the Sipsey Fork of the Black Warrior River to form the lake.
Because the malaria species Plasmodium vivax normally uses DARC to enter red blood cells, people who carry this mutation are resistant to one strain of malaria. This particular strain of malaria is not a major killer in Africa today, but was likely more threatening in the past. Biologists reason that the DARC mutant arose in Africa through random mutation and began to spread through the process of natural selection.
Human malaria is caused by infection with intracellular parasites of the genus Plasmodium that are transmitted by Anopheles mosquitoes. Of the four species of Plasmodium that infect humans, Plasmodium falciparum is the most lethal. Resistance to anti-malarial drugs and insecticides, the decay of public health infrastructure, population movements, political unrest, and environmental changes are contributing to the spread of malaria.