Workers unload medical supplies to fight the Ebola epidemic from a USAID cargo flight in Harbel, Liberia, in August. John Moore/Getty Images hide caption

itoggle caption John Moore/Getty Images

Medical workers at the John F. Kennedy Medical Center in Monrovia, Liberia, put on their protective suits before going to the high-risk area of the hospital, where Ebola patients are being treated, Sept. 3. Dominique Faget/AFP/Getty Images hide caption

itoggle caption Dominique Faget/AFP/Getty Images

Dr. Rick Sacra, 51, has been working on and off in Liberia for 15 years. He went back to Monrovia in August to help deliver babies. It's still unknown how he caught Ebola. Courtesy of SIM hide caption

itoggle caption Courtesy of SIM

US soldiers have intervened in during natural disasters such as the 2010 earthquake in Haiti. But a disease outbreak is more complicated. SSgt. Chad Chisholm/U.S. Dept. of Defense hide caption

itoggle caption SSgt. Chad Chisholm/U.S. Dept. of Defense

Not every business has been hurt by the Ebola epidemic: Stephen Kollie says his newspaper stand is thriving because people are hungry for the latest Ebola information. But many of his usual expatriate customers have left the country, he says. Tommy Trenchard for NPR hide caption

itoggle caption Tommy Trenchard for NPR

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

Workers wait to spray disinfectant on medical staff after they treat Ebola patients at a clinic run by Doctors Without Borders, in Monrovia, Liberia. Tommy Trenchard for NPR hide caption

itoggle caption Tommy Trenchard for NPR

Air traffic connections from West Africa to the rest of the world: While Guinea, Liberia and Sierra Leone don't have many flights outside the region, Nigeria is well-connected to Europe and the U.S. PLOS Currents: Outbreaks hide caption

itoggle caption PLOS Currents: Outbreaks

Barbara Bush helps a nun to fit on a hearing device during a 2012 event in Gulu, Uganda. She says was interested in architecture as a college student but became a global health activist after visiting East Africa with her parents. Reuters/Landov hide caption

itoggle caption Reuters/Landov

A technician tests samples from Ebola-infected patients at a field lab, run by Doctors Without Borders, in Kailahun, Sierra Leone. Tommy Trenchard for NPR hide caption

itoggle caption Tommy Trenchard for NPR

A scientist tests a patient's blood for Ebola at the European Mobile Laboratory in Gueckedou, Guinea. The first cases reported in the outbreak occurred in a small village about eight miles outside Gueckedou. Misha Hussain /Reuters /Landov hide caption

itoggle caption Misha Hussain /Reuters /Landov

Jude Law prepares for the looming pandemic in the 2011 movie Contagion. There are huge differences between viruses in movies and Ebola in real life. Warner Bros/The Kobal Collection hide caption

itoggle caption Warner Bros/The Kobal Collection