Zika virus has been earning all the headlines, because it is already affecting Americans—including 300 pregnant women, according to a new CDC estimate—and is expected to move into U.S. mosquitoes as the summer bug season starts.

But outside the United States, another mosquito-borne disease is attracting the world’s attention, and it may predict more than Zika does about how epidemics will move around the world in the future. The disease is yellow fever, the epicenter of the outbreak is Angola, and the force that could push it around the globe is Chinese investment in the developing world.

The Angolan outbreak began in December and is large: more than 2,400 cases and 298 deaths, according to