Engineers with the armed forces of Liberia install a drainage culvert at a new Ebola treatment unit being built in support of Operation United Assistance in Gbediah, Liberia, Dec. 19, 2014. United Assistance is a Department of Defense operation to provide command and control, logistics, training and engineering support to U.S. Agency for International Development-led efforts to contain the Ebola virus outbreak in West African nations. (U.S. Army Photo by Sgt. 1st Class Brien Vorhees, 55th Signal Company (Combat Camera) / Released)