Emerging Artemisinin Partial Resistance in Southern Africa.

A new focus of probable artemisinin-partial resistance (ART-R) has been identified in southern Africa, driven by the P441L mutation in the Plasmodium falciparum Kelch13 gene. This emerging cross-border cluster across Angola, Namibia, and Zambia represents the fourth major ART-R focus identified in Africa, adding to the previously reported foci in East Africa and the Horn of Africa. Findings from three new studies reveal 7.3%, 33%, and 47% prevalence of P441L in specific sites in Angola, Namibia, and Zambia, respectively. The Genomics of Malaria in the Elimination 8 project enabled harmonized, real-time molecular surveillance across five countries, providing actionable data for national malaria programs. Given past failures to contain chloroquine and sulfadoxine-pyrimethamine resistance, a timely response is critical. We recommend immediate treatment policy shifts, expanded surveillance, and regional coordination to prevent the spread of ART-R. This Perspective calls on global health actors to act decisively while resistance remains geographically limited.