Ramatu Usman, shown here with one of her sons, is a 37-year-old mother of eight. She says she was separated from one of her sons, 6-year-old Yahaya Buba, following an attack. He is still missing. Ofeibea Quist-Arcton/NPR hide caption

itoggle caption Ofeibea Quist-Arcton/NPR

People inspect the site of a suicide bomb explosion at the Government Science Technical College in Potiskum, Nigeria, Monday. Survivors say a bomber disguised in a school uniform detonated explosives during an assembly at the school. Adamu Adamu/AP hide caption

itoggle caption Adamu Adamu/AP

A child receives a polio vaccine during National Immunization Days in the Nigerian city of Kano. Diego Ibarra Sanchez /Courtesy of Rotary Foundation hide caption

itoggle caption Diego Ibarra Sanchez /Courtesy of Rotary Foundation

People call for the Nigerian government to rescue girls taken from a secondary school in Chibok region, during a protest earlier this month. Boko Haram, the group that took the girls, says they have been "married off." Olamikan Gbemiga/AP hide caption

itoggle caption Olamikan Gbemiga/AP

Earlier this month, people demonstrated in Nigeria's capital, Abuja, calling on the government to rescue girls taken from a secondary school in Chibok region in April. Now there are reports that militants of the extremist Boko Haram movement have kidnapped more girls. Olamikan Gbemiga/AP hide caption

itoggle caption Olamikan Gbemiga/AP

At the onset of symptoms, Dr. Adaora Igonoh (center) and her colleagues began drinking oral rehydration solution. It doesn't taste great but they say it helped them survive Ebola. They each downed over a gallon a day for nearly a week. Andrew Esiebo/Courtesy of WHO hide caption

itoggle caption Andrew Esiebo/Courtesy of WHO

Dutch Foreign Minister Bert Koenders (center) speaks with Luxembourg Foreign Minister Jean Asselborn (second from left) and British Foreign Minister Philip Hammond (right) during a round table meeting of EU foreign ministers in Luxembourg on Monday. The ministers hope to raise 1 billion euros to fight Ebola. Virginia Mayo/AP hide caption

itoggle caption Virginia Mayo/AP

A security man takes visitors' temperatures Wednesday at the Transcorp Hilton hotel in Abuja, Nigeria, about 400 miles north of Port Harcourt. Afolabi Sotunde/Reuters/Landov hide caption

itoggle caption Afolabi Sotunde/Reuters/Landov

This week, Pakistani activist Malala Yousafzai met with some of the girls who escaped Boko Haram's captivity. The Islamic extremist group gained attention in April when it kidnapped more than 200 girls from a school in northeastern Nigeria. Many girls are still missing. Olamikan Gbemiga/AP hide caption

itoggle caption Olamikan Gbemiga/AP

Nigeria's chief of defense staff Air Marshal Alex S. Badeh speaks during a demonstration in Abuja calling for the rescue of girls kidnapped from their school in Chibok. Badeh says the government knows where the girls are — but that a rescue attempt would endanger their lives. Gbenga Olamikan/AP hide caption

itoggle caption Gbenga Olamikan/AP

Defense Secretary Chuck Hagel speaks during a news conference after attending the Gulf Cooperation Council meeting in Jiddah, Saudi Arabia, on Wednesday. Hagel confirmed that the U.S. was using drones to search for 270 kidnapped Nigerian schoolgirls. Mandel Ngan/AP hide caption

itoggle caption Mandel Ngan/AP

Demonstrators call for the release of girls kidnapped from a school in Nigeria, during a demonstration in Lagos on Monday. A woman has said her daughter is in a video released by Boko Haram, the group that took the girls last month. Pius Utomi Ekpei/AFP/Getty Images hide caption

itoggle caption Pius Utomi Ekpei/AFP/Getty Images

The effort to find hundreds of abducted Nigerian schoolgirls has gone international — and so has anger over the mass kidnapping, as evidenced by this protest Thursday in South Africa. Retired Gen. Carter Ham says there's still a chance for the U.S. to help. Ben Curtis/AP hide caption

itoggle caption Ben Curtis/AP