It may, in the end, turn out to be fortunate that a handful of people in developed countries — four in the United States and one in Spain — have contracted Ebola. Tragic as this was for Thomas Duncan, the only one of these patients who has died, if all of the more than 13,000 cases and nearly 5,000 deaths had occurred in Africa, Ebola would never have aroused nearly as much attention in rich countries.

In this respect, Ebola is — or, rather, was — an example of what is sometimes referred to as the 90/10 rule: 90 percent of medical research is directed toward illnesses that comprise only 10 percent of the global burden of disease. The world has known about the deadly nature of the Ebola virus since 1976; but, because its victims were poor, pharmaceutical companies had no incentive to develop a vaccine. Indeed, pharmaceutical companies could expect to earn more from a cure for male baldness.

Government research funds in affluent countries are also disproportionately targeted toward the diseases that kill these countries' citizens, rather than toward diseases like malaria and diarrhea that are responsible for much greater loss of life.