Over the course of history, yellow fever has paralyzed governments, halted commerce, quarantined cities, moved the U.S. capital, and altered the outcome of wars. During a single summer in Memphis alone, it cost more lives than the Chicago fire, the San Francisco earthquake, and the Johnstown flood combined. In 1900, the U.S. sent three doctors to Cuba to discover how yellow fever was spread. There, they launched one of history's most controversial...