By taking antiretroviral drugs during pregnancy, this Tanzanian mother lowered the risk of passing HIV to her daughter. Siegfried Modola/AFP/Getty Images hide caption

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Many homes that were rebuilt after the earthquake in 2010 are even more dangerous than the original ones. This three-story home was put up after the quake but is already slated for demolition to make way for an 18-unit housing project. David Gilkey/NPR hide caption

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Partnerships instead of short-term help: Jean Jumeau Batsch, an obstetrician-gynecologist in Port-au-Prince, Haiti, is collaborating with Dr. Ambereen Sleemi, from New York City, to build a training program for Haitian OB-GYNs. Courtesy of Dr. Ambereen Sleemi. hide caption

itoggle caption Courtesy of Dr. Ambereen Sleemi.

As an armchair disease detective, you don't have to bother with mundane tasks, like culturing fluorescent bacteria or interviewing the ill. Centers for Disease Control and Prevention hide caption

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HIV drugs not only can keep patients healthy but also can stop the sexual transmission of the virus. Here an HIV-positive mother picks up medications at a hospital outside Johannesburg, South Africa. Alexander Joe/AFP/Getty Images hide caption

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Health officials around the world are on constant lookout for the deadly bird flu. Here a worker collects chickens on a farm in Kathamndu, Nepal, where the virus was suspected of infecting poultry last October. Prakas Mathema/AFP/Getty Images hide caption

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Coronaviruses have a characteristic crown of tentacles when viewed under the electron microscope. BSIP/UIG via Getty Images hide caption

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Shoppers buy smuggled counterfeit drugs at the Adjame market in Abidjan, Ivory Coast, in 2007. Issouf Sanogo/AFP/Getty Images hide caption

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Virologists discovered the new coronavirus after it killed a Saudi Arabian man last summer. Elizabeth R. Fischer/Rocky Mountain Labs/NIAID/NIH hide caption

itoggle caption Elizabeth R. Fischer/Rocky Mountain Labs/NIAID/NIH

A Nigerian health commissioner Dr. Sani Malam vaccinates a child for polio during a national immunization drive in Bauchi, Nigeria, last week. Deji Yake/EPA /Landov hide caption

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An artist on Rio de Janeiro's Copacabana beach puts the final touches on a sand sculpture of the kissing bug, which spreads Chagas' disease. The sculpture was part of an event in 2009 commemorating the 100th anniversary of the discovery of the disease. Vanderlei Almeida/AFP/Getty Images hide caption

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Nurse Christel Petersen inoculates a child in the South African Tuberculosis Vaccine Initiative study in 2011. Rodger Bosch/AFP/Getty Images hide caption

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