Sam Sells, right, military liaison for U.S. Agency for International Development, speaks with Emmanuel Tucker, site engineer, about progress on the new Ebola treatment unit to be built as a part of Operation United Assistance in Zorzor, Liberia, Nov. 18, 2014. United Assistance is a Department of Defense operation to provide command and control, logistics, training and engineering support to USAID-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)