Why is Ebola less deadly in America than in Africa?

So far, every story of an American infected with Ebola has ended happily, most recently, with today's news that Dallas nurse Nina Pham — the first patient to contract Ebola in the US — has been discharged from hospital, Ebola-free.

Beating the virus has become a familiar, almost expected, narrative here: Seven out of the eight Ebola patients treated in the United States have survived. These are hugely better outcomes than in Africa, where approximately 70 percent of patients die.It is true that the average West African has a lower life expectancy than the average American. And a much smaller number of Americans have so far contracted, and been treated for, Ebola. But those who have show remarkably good results. "Yes, it’s a small sample size," says Dr. Ashish Jha, director of the Harvard Global Health Institute, adding that there are still "enough data points to say there's something meaningfully different."