Increasing evidence suggests that our species emerged through interactions between populations living in different parts of Africa, rather than from a single birthplace. Until now, however, most explanations for how those populations were distributed across the continent have focused on climate alone. The new research shows that disease—specifically malaria—also played a crucial role.

In a paper published in Science Advances, researchers from the Max Planck Institute of Geoanthropology, the University of Cambridge, and colleagues have investigated whether Plasmodium falciparum-induced malaria shaped human habitat choice between 74,000 and 5,000 years ago, the critical period before humans dispersed widely beyond Africa and before agriculture dramatically altered malaria transmission.

The study shows that malaria, one of humanity’s oldest and most persistent pathogens, influenced habitat choice by pushing human groups away from high-risk environments and separating populations across the landscape. Over tens of thousands of years, this fragmentation shaped how populations met, mixed, and exchanged genes, helping create the population structure seen in humans today. The findings suggest that infectious disease was not simply a challenge early humans faced: it was a fundamental factor shaping the deep history of our species.