On July 20 a man who was ill flew on commercial planes from the heart of the Ebola epidemic in Liberia to Lagos, Nigeria's largest city. That man became Nigeria's first Ebola case—the index patient. In a matter of weeks some 19 people across two states were diagnosed with the disease (with one additional person presumed to have contracted it before dying).
Source: http://www.ereporter.com.ng/index.php/more-news/health-news2/item/607-how-did-nigeria-quash-its-ebola-outbreak-so-quickly