A new study suggests that malaria influenced where early humans lived in sub-Saharan Africa between around 74,000 and 5,000 years ago, fragmenting populations and influencing patterns of genetic exchange long before recorded history.
By fragmenting human societies across the landscape, malaria contributed to the population structure we see today.
Andrea Manica
The presence of malaria affected where human populations lived across sub-Saharan Africa between 74,000 and around 5,000 years ago, a new study has found.
Over tens of thousands of years, the presence of this disease shaped how human populations met and mixed - allowing genes to be exchanged, and 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 course of human evolution.
The researchers say malaria may have driven populations away from high-risk environments and separated them across the landscape, or it may have caused high death rates in specific areas.
Increasing evidence suggests that modern humans 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.
The results are published today in the journal Science Advances.
To reach their results, the team started with present-day distribution maps of Africa's main malaria‑transmitting mosquito species. Then they used climate models to reconstruct how the ranges of these mosquitoes shifted over the past 74,000 years, alongside estimates of likely malaria transmission intensity. Finally, they compared these results with archaeological maps of ancient human settlements, and looked at where and when humans and malaria potentially overlapped.
"We estimated the risk of malaria transmission across sub-Saharan Africa over the past 74,000 years, and found that ancient humans were not living in high-risk areas for the majority of this time," said Dr Margherita Colucci in the University of Cambridge's Department of Zoology, first author of the study.
Colucci, who is also a researcher at the Max Planck Institute of Geoanthropology, added: "Our results indicate that ancient human populations strongly avoided, or were unable to survive in, areas with high malaria transmission risk. The effects of these choices shaped human demography for the majority of the last 74,000 years, and likely much earlier."
"By fragmenting human societies across the landscape, malaria contributed to the population structure we see today. Our study suggests that climate and physical barriers were not the only forces shaping where human populations could live," said Professor Andrea Manica in the University of Cambridge's Department of Zoology, a co-senior author of the study.
The researchers found an increasing geographic overlap between human populations and malaria-carrying mosquitoes after around 15,000 years ago, beginning in West Africa. This coincides with the appearance of a human genetic mutation that gave rise to sickle-cell anaemia - and also provides partial protection against malaria.
Until now, the emergence of infectious diseases affecting human populations was thought to be linked with the domestication of crops and the transition away from a hunter-gatherer lifestyle, thought to have begun around 8,000-7,000 years ago.
Scientists have struggled to investigate the impact of disease on humanity's early history due to a lack of direct evidence. The oldest ancient pathogen DNA, for example, is only around 10,000 years old, with the majority only from the last 2-3,000 years. In this study, the researchers used novel methods combining multiple lines of evidence that allowed them to reach much further back into the past.
74,000 years ago is a common time point for researchers to stop at when looking into the past. It coincides with the Toba supervolcano eruption - the largest known explosive eruption in human history.
"Disease has rarely been considered a major factor shaping the earliest prehistory of our species, and without ancient DNA from these periods it has been difficult to test. Our research changes that, and provides a new framework for exploring the role of disease in deep human history," said Professor Eleanor Scerri at the Max Planck Institute of Geoanthropology, also a senior author of the study.
This research was funded by the Max Planck Institute of Geoanthropology.
Reference: Colucci, M. et al: 'Malaria shaped human spatial organization for the past 74 thousand years'. Science Advances, April 2026. DOI: 10.1126/sciadv.aea2316
Adapted from a press release by the Max Planck Institute of Geoanthropology.
