The bite of a cobra can paralyze its victims and, if enough venom is released, fatally stop their breathing. It's estimated that more than 75 percent of patients in India who die from a snake's bite never make it to the hospital. STRDEL/AFP/Getty Images hide caption

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Some images of lung cancer are clear cut. But in many others, a nodule on the screen turns out not to be cancer at all. iStockphoto.com hide caption

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Ads often tout dietary supplements and vitamins as "natural" remedies. But studies show megadoses of some vitamins can actually boost the risk of heart disease and cancer, warns Dr. Paul Offit. iStockphoto.com hide caption

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Vaccines against the HPV virus are already used to prevent cervical and anal cancer. Harry Cabluck/AP hide caption

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A Doctors Without Borders support counselor waits for MDR-TB patients at a clinic in Nukus, Uzbekistan. Courtesy of Misha Friedman hide caption

itoggle caption Courtesy of Misha Friedman

Red blood cells are normally shaped like doughnuts, but sickle cells (purple) are flattened and clump together. NIH hide caption

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A woman waits to get AIDS drugs on April 8 at a clinic in Ga-Rankuwa, South Africa, about 55 miles north of Johannesburg. New WHO guidelines say patients should start HIV treatment much earlier, before they become extremely sick. Stephane de Sakutin/AFP/Getty Images hide caption

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Michael Pagliaro, left, laughs with Paul Scattaretico at the Muzic Store Inc. in Dobbs Ferry, N.Y., as Pagliaro picks up instruments for his rental business. Before Pagliaro had a hip replacement, pain made it difficult to work. Maggie Starbard/NPR hide caption

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Craig Rowles tends to his pigs in a barn near Carroll, Iowa. Dan Charles/NPR hide caption

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In 2008, Michael Mastromarino was sentenced in a New York City courtroom for enterprise corruption, body stealing and reckless endangerment. Jesse Ward/AP hide caption

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