How do siblings get around the "no touching" rule during the Ebola outbreak in Sierra Leone? Alex and Jen Tran grabbed a rare hug when they were geared up for training. Courtesy of Alex Tran hide caption

itoggle caption Courtesy of Alex Tran

In this 2012 photograph, Adamu Ali carries his 4-year-old son, Omar, who was stricken with polio earlier that year. They live in the Nigerian village of Minjibir. David Gilkey/NPR hide caption

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Boys run from blowing dust as a U.S. Marine vehicle takes off from an Ebola treatment center under construction in Liberia in October. In the end, the centers weren't always needed, but the military's ability to ferry supplies was critical in fighting the outbreak. John Moore/Getty Images hide caption

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This World Health Organization map shows the percent of the population vaccinated for measles in each country in 2013. Dark green is at least 90 percent. Light green is 80 to 89 percent. Orange is 50 to 79 percent. Red is less than 50 percent. Courtesy of WHO hide caption

itoggle caption Courtesy of WHO

Dr. Margaret Chan, director-general of the World Health Organization, has said of Ebola: "It overwhelmed the capacity of WHO, and it is a crisis that cannot be solved by a single agency or single country." Fabrice Coffrini/AFP/Getty Images hide caption

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A new study finds that strenuous labor in the sugar cane fields of Central America is contributing to a mysterious form of kidney failure. Above: Workers harvest sugar cane in Chichigalpa, Nicaragua. Jason Beaubien/NPR hide caption

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In November, women in El Salvador marched for the freedom of 17 women accused of abortion, including Carmen Guadalupe Vasquez Aldana. She was pardoned this week. Luis Galdamez/Xinhua /Landov hide caption

itoggle caption Luis Galdamez/Xinhua /Landov

Indian sand artist Sudersan Pattnaik touches up his sculpture for World No Tobacco Day at Golden Sea Beach in Puri, India. Asit Kumar/AFP/Getty Images hide caption

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This photo was taken in November, a tough month for Sierra Leone, with Ebola cases reportedly on the rise. A staff member is disinfecting an office where Dr. Komba Songu M'Briwah talks on the phone. David Gilkey/NPR hide caption

itoggle caption David Gilkey/NPR