In this photo taken on Monday, Aug. 4, 2014, health workers, left, traveling by motorbike with others inside a truck, right, as they attempt to educate people about the deadly Ebola virus in the city of Freetown, Sierra Leone. The global Ebola outbreak touched American shores more definitively Monday, as Atlanta awaited the arrival of its second Ebola patient by morning, and a New York hospital announced it had isolated a man with possible symptoms who walked into its emergency room.(AP Photo/ Youssouf Bah)
As health officials fight to contain the deadly Ebola virus, the picture of how the disease spread so rapidly, and how officials failed to respond effectively, is emerging.
One factor experts looking at is the changing lifestyle in West African countries, where increasing travel and urbanization is posing new risks to the spread of disease.
Dr. Jeffery Sachs, director of the Earth Institute at Columbia University, spoke with Take Two on the subject on Tuesday.