When Amber Vinson walked out of Emory University Hospital in Atlanta on Tuesday, she became the sixth person in the country to be successfully treated for a disease that kills 70% of its victims in Africa, but has so far killed only one in the United States. Long thought to be a death sentence, Ebola has proved vulnerable to a mix of standard and invasive medical techniques, readily available in the U.S. but often beyond the reach of the impoverished nations at the heart of the outbreak. Breathing tubes, large-bore intravenous lines, blood dialysis, electrolyte monitoring and around-the-clock attention are largely responsible for the survival of patients under advanced Western care,...