Twins in Malawi helped scientists discover a role the gut microbiome appears to play in severe malnutrition. Photograph courtesy of Tanya Yatsunenko hide caption

itoggle caption Photograph courtesy of Tanya Yatsunenko

The British have long said, "Keep calm and carry on." But the catchphrase may need an update for health care. Keepcalm-o-matic.co.uk hide caption

itoggle caption Keepcalm-o-matic.co.uk

Health workers in Nepal culled chickens and destroyed eggs following an outbreak of bird flu in Kathmandu in October 2012. Prakash Mathema/AFP/Getty Images hide caption

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Harvest wheat from a field near Wright, Kan. May 10, 2004. ORLIN WAGNER/ASSOCIATED PRESS hide caption

itoggle caption ORLIN WAGNER/ASSOCIATED PRESS

A boy with multiple Guinea worms sits outside a containment center in northern Ghana, February 2007. Wes Pope/Chicago Tribune/MCT /Landov hide caption

itoggle caption Wes Pope/Chicago Tribune/MCT /Landov

A copper engraving from 1656 shows a plague doctor in Rome wearing a protective suit and a mask. Artwork by Paul Furst /Wikimedia.org hide caption

itoggle caption Artwork by Paul Furst /Wikimedia.org

Microbiologist Emma Allen-Vercoe invented the Robogut, a mechanical device that mimics conditions in the human colon. Courtesy of thestar.com hide caption

itoggle caption Courtesy of thestar.com

Haitians protest against the United Nations peacekeepers in Port-au-Prince in November 2010. Hector Retamal/AFP/Getty Images hide caption

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Jacqueline Syra has been living in the La Piste camp for three years. She says she has no idea when she will be able to leave. David Gilkey/NPR hide caption

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Jan. 9, 2013 David Gilkey/NPR hide caption

itoggle caption David Gilkey/NPR