A U.S. Marine Corps MV-22B Osprey sits on the flight line at Roberts International Airport preparing to transport personnel to an Ebola treatment unit site in River Gee, Liberia, Nov. 17, 2014. The Osprey is a primary source of transportation for the Special-Purpose Marine Air-Ground Task Force – Crisis Response in support of Operation United Assistance. United Assistance is a Department of Defense operation in Liberia to provide logistics, training and engineering support to U.S. Agency for International Development-led efforts to contain the Ebola virus outbreak in western Africa. (U.S. Army photo by Pfc. Rashene Mincy, 55th Signal Company (Combat Camera)/Released)