The Centers for Disease Control and Prevention's PulseNet service monitors clusters of sickness linked to potentially dangerous strains of foodborne pathogens such as E.coli or salmonella. Reed Saxon/AP hide caption

itoggle caption Reed Saxon/AP

The Eagle Mountain Church in Newark, Texas, was linked to at least 21 cases of measles this year, mostly in children. LM Otero/AP hide caption

itoggle caption LM Otero/AP

A new study from the Centers for Disease Control and Prevention finds no link between the number of vaccinations a young child receives and the risk of developing autism spectrum disorders. Jeff J. Mitchell/Getty Images hide caption

itoggle caption Jeff J. Mitchell/Getty Images

A woman uses a cellphone while driving in Los Angeles in 2011. Damian Dovarganes/AP hide caption

itoggle caption Damian Dovarganes/AP

Klebsiella pneumoniae, seen here with an electron microscope, are the most common superbugs causing highly drug-resistant infections in hospitals. Kwangshin Kim/Science Source hide caption

itoggle caption Kwangshin Kim/Science Source

Kimberly Delp gives a flu shot to Carleen Matthews at the Homewood Senior Center in Pittsburgh, Pa., last September. Andrew Rush/AP hide caption

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More than 400 guns, including these three, were turned in during a Dallas gun buyback program in January. But determining the effectiveness of such programs is difficult due to limits on gun-related research. Tom Pennington/Getty Images hide caption

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