Outbreak, Frontline.

FRONTLINE tells the vivid, inside story of how the Ebola outbreak began, and why it wasn't stopped before it was too late.

2014 Ebola Outbreaks, Healthmap.org.

This interactive timeline shows the spread of Ebola, starting with the first index cases in 2013 through the end of the epidemics in January of 2016.

Ebola and Contact Tracing, Centers for Disease Control and Prevention.

"This video describes contact tracing, a method used by CDC and partners to identify new Ebola cases quickly and isolate patients as soon as they show symptoms, preventing spread to others. The video demonstrates how even one missed contact can keep Ebola spreading and that careful tracing of contacts and isolating new cases can stop the outbreak."

Contact tracing means finding everybody who has come in contact with an infected person. In the case of Ebola, contacts are watched for 21 days. If they become sick they are isolated and contact tracing with that person begins again.