Ebola in Liberia: See the Challenges U.S. Mission Faces

— -- ABC News goes into Liberia's remote villages, where few outsiders are welcomed, to show the biggest challenges to the United States' Ebola mission.

Hard-to-reach frontier towns are becoming the new frontlines for the Ebola outbreak -- even as the number of new cases in Liberia has been falling in recent weeks. The distrust, denial and deaths there could make Ebola difficult to eradicate and U.S. Operation United Assistance difficult to end.