U.S. officials headed to Nigeria to learn how it contained Ebola using 'contact tracing'

Nigerian Health Minister - Prof. Onyebuchi Chukwu

The Christian Science Monitor - When Ebola reached Nigeria, health officials were worried about the populous country's ability to control the virus – particularly in Lagos, the nation’s coastal mega-city and transport hub. 
But this week, teams of American health officials are Lagos-bound to learn from Nigeria's experience in defying expectations and stopping the outbreak before it could wreak havoc. 
Since July 20, the day Nigeria’s so-called “Patient Zero” arrived in Lagos, officials have recorded a total of only 19 cases, with no new cases since Aug. 31. Last week, on the same day the US confirmed its first case of Ebola, the Center for Disease Control (CDC) proclaimed that Nigeria had stopped its outbreak. 
Meanwhile, Sierra Leone, one of three West African countries hard hit by Ebola, recorded 81 new cases in the past 24 hours.
"Because of a rapid public health response, effectively tracking nearly 900 contacts, it appears they have] been able to stop the outbreak in Nigeria,” CDC Director Tom Frieden said Sunday. “Though we can't give the all clear yet, it does look like the outbreak is over there. I'm confident that wherever we apply the fundamental principles of infection control in public health, we can stop Ebola."
Nigeria’s success appears to be rooted in "contact tracing" – determining every single person that Patrick Sawyer, or Patient Zero, had contact with, and then monitoring them for signs of the virus.
 “Contact tracing can stop the Ebola outbreak in its tracks,” a chart distributed by the CDC declares. 
Now contact tracers are at work in the US, setting out to track down as many as 100 people who may have been exposed to Thomas Duncan, who traveled from Liberia to Dallas, where he was eventually diagnosed with the virus, The New York Times reports. 
It is an immense task. The Washington Post outlines how it went in Nigeria:

From that single patient came a list of 281 people, [Gavin MacGregor-Skinner, who helped with the Ebola response in Nigeria] said. Every one of those individuals had to provide health authorities twice-a-day updates about their well-being, often through methods like text-messaging. Anyone who didn't feel well or failed to respond was checked on, either through a neighborhood network or health workers. ...In the end, contact tracers — trained professionals and volunteers — conducted 18,500 face-to-face visits to assess potential symptoms, according to the CDC, and the list of contacts throughout the country grew to 894. Two months later, Nigeria ended up with a total of 20 confirmed or probable cases and eight deaths. 

 Ethiopia, one of two countries recognized by the World Health Organization as prepared for a possible Ebola outbreak, also has a vigorous tracing process that applies to every visitor from West Africa.