Population genomics of Plasmodium ovale species in sub-Saharan Africa

Plasmodium ovale curtisi (Poc) and Plasmodium ovale wallikeri (Pow) are relapsing malaria parasites endemic to Africa and Asia that were previously thought to represent a single species. Amid increasing detection of ovale malaria in sub-Saharan Africa, we performed a population genomic study of both species across the continent. We conducted whole-genome sequencing of 25 isolates from central and east Africa and analyzed them alongside four previously published west and central African genomes. Isolates were predominantly monoclonal (27/29), with their genetic similarity aligning with geography. Pow showed lower average nucleotide diversity (1.9x10-4) across the genome compared to Poc (2.8x10-4) (p < 0.0001). Signatures of selective sweeps involving the dihydrofolate reductase gene were found in both species, as were signs of balancing selection at the merozoite surface protein 1 gene. Differences in the nucleotide diversity of Poc and Pow may reflect unique demographic history, even as similar selective forces facilitate their resilience to malaria control interventions. ### Competing Interest Statement J.B.P. reports research support from Gilead Sciences, non-financial support from Abbott Laboratories, and consulting for Zymeron Corporation, all outside the scope of this study. The remaining authors declare no competing interests.