Seeds from Golden Rain acacias like these in Wales provide the active ingredient for a pill to help people stop smoking. Tom Patterson/Flickr hide caption

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A nurse vaccinates a child against pneumonia at a healthcare center in Managua in January. Nicaragua received pneumococcal vaccines from the GAVI Alliance. ELMER MARTINEZ/AFP/Getty Images hide caption

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A man readies a cow for the International Highland Cattle Show in Glasgow, Scotland. Researchers say genetics and the amount of time animals and humans spend together can affect how viruses spread between species. Jeff J Mitchell/Getty Images hide caption

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A pizza from a Pizzomatic vending machine that bakes and sells pizzas in Germany. Public health advocates say the food industry needs to make concrete commitments to making healthier products to reduce chronic disease related to diet. OLIVER BERG/AFP/Getty Images hide caption

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Trevor Reese, 13, gets his diphtheria, tetanus and pertussis booster shot from pediatric nurse practitioner Jenny Lu in Tustin, Calif., in August. Jae C. Hong/AP hide caption

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Nengah, 35, suffers from schizophrenia. Until recently, her family on Bali in Indonesia kept her chained to a concrete pit for nearly a decade. Cokorda Bagus Jaya Lesmana/Courtesy of GlobalPost hide caption

itoggle caption Cokorda Bagus Jaya Lesmana/Courtesy of GlobalPost

Two women check their cellphones as they hawk their wares on a bridge over the Artibonite River, whose waters are believed to be the source of Haiti's 2010 cholera outbreak. Nicholas Kamm/AFP/Getty Images hide caption

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