Who's there? A radiologist studies digital X-rays in a viewing room at what is now called the Walter Reed National Military Medical Center in Bethesda, Md. Seth Rossman/U.S. Navy hide caption

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Spinach has lots of opportunities to pick up E. coli and other bugs during harvest and growing. Here, a Mexican migrant worker cuts organic spinach during the fall harvest at Grant Family Farms in Wellington, Co. John Moore/Getty Images hide caption

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Scientists say that the best way to reduce a person's contact with the flame retardant chemicals in sofas and other furniture is to vacuum more. SINAN DONMEZ/iStockphoto.com hide caption

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At a Los Angeles media briefing in 2010, Mariah Bianchi describes how her own case of whooping cough caused the death of her newborn son. Reed Saxon/AP hide caption

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Grapefruit can make for a tasty addition to breakfast. But it can also interfere with some medications. iStockphoto.com hide caption

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Hospitals began testing blood for hepatitis in 1992, so anyone who received a blood transfusion before then is at an increased risk for contracting the disease. iStockphoto hide caption

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The Lone Star tick, common to the southeastern U.S., is responsible for inducing meat allergies in some people, scientists say. CDC Public Health Image Library hide caption

itoggle caption CDC Public Health Image Library

A Hare Krishna distributes food gifts from a chariot during a festival in London in 2011. The religious group began distributing books, flowers and gifts to strangers in the 1970s, drawing on the rule of reciprocation to raise money. Matthew Lloyd/Getty Images hide caption

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A mammographer prepares a screen-film mammography test for patient Alicia Maldonado at a hospital in Los Angeles. Damian Dovarganes/AP hide caption

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