Two men from northwestern Missouri became ill after tick bites infected them with a previously unknown virus. iStockphoto.com hide caption

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A Beechcraft airplane sprays insecticide over Dallas early Monday morning to curb the spread of West Nile virus. LM Otero/AP hide caption

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Though scientists have identified sleepwalking triggers, the condition is still a bit of a mystery. Victoria Alexandrova/iStockphoto.com hide caption

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Ashley Beecher, 29, and her daughters Annie (on lap) and Charlie. After feeding Annie, Beecher donates her extra supply to the human milk bank at Texas Children's Hospital. KUHF hide caption

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Scientists say energy-saving compact fluorescent (left) or light-emitting diode (right) light bulbs can have unsavory health effects. PRNewsFoto/OSRAM SYLVANIA hide caption

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The Opening Ceremony of the London 2012 Olympic Games included a paean to the National Health Service, the U.K.'s socialized healthcare system. Gallo/Getty Images hide caption

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Megan Lutz, left, and Justin Chun react to amateur comedian Robert Lynch at the Metropolitan Room in Manhattan, N.Y. Lynch is an anthropologist researching what laughing reveals about us. Melanie Burford for NPR hide caption

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Devotees take part in rituals and offer gifts in celebration of Yemanja Day, in Salvador, Bahia state, Brazil, in February. Ricardo Cardosa/DPA /Landov hide caption

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Can You Help Me Tie My Shoe? Researchers found that when study participants were asked an unusual request, they were more likely later on to perform a favor. iStockphoto.com hide caption

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At the International AIDS conference, a female condom fashion show raised awareness about the rising need for more female condoms. Olwin Manyanye of Zimbabwe shows off one of the dresses decorated with a second-generation female condom, called "FC2." Benjamin Morris/NPR hide caption

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