Contents

03 July 2013
Vol 5, Issue 192

About The Cover

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ONLINE COVER Resisting an Ancient Scourge. Cholera is an ancient disease caused by the bacterium Vibrio cholerae. This bacterium invades the small intestine where it produces a toxin that induces secretion of water and chloride, potassium and sodium ions into the gut lumen resulting in severe diarrhea and dehydration that is often fatal. Cholera remains endemic in many parts of the developing world, including the Ganges River Delta. A genome-wide association study of a population in Bangladesh living in a cholera-endemic area reveals positive selective pressure on genes encoding potassium channels involved in chloride secretion and components of the innate immune system (Karlsson et al.) These findings shed light on the pathogenesis of cholera and identify factors that might increase resistance to cholera infection. [CREDIT: SIGRID KNEMEYER/BROAD INSTITUTE; MSLIGHTBOX/ISTOCKPHOTO]