Emergence and Rising Prevalence of Artemisinin Partial Resistance Marker Kelch13 P441L in a Low Malaria Transmission Setting in Southern Zambia.

Increasing artemisinin partial resistance (ArtR) due to mutations in the gene encoding Kelch13 () protein in eastern Africa is of urgent concern, and mutations, such as P441L, continue to emerge. We used an amplicon deep-sequencing panel to estimate the prevalence of ArtR mutations in samples collected between 2018 and 2023 in southern Zambia. P441L was present in 30 of 501 samples (6%), and prevalence increased over time (0% to 7.2%). Further studies of the P441L mutation are needed to document its geographical origin, distribution and impact on treatment outcomes.