Sierra Leone's leading doctor died of Ebola on Thursday, Reuters reports. Victor Willoughby was diagnosed last week after treating a patient, who also died of Ebola.Willoughby is the 11th doctor in the nation to die of the virus, out of 12 diagnosed. Sierra Leone has the fastest-rising infection rate and more than half of the 18,603 Ebola cases worldwide.Willoughby's death came hours after an experimental drug arrived in the country frozen on an airplane, the government's chief medical officer told Reuters.