Absence of Validated and Candidate Plasmodium falciparum Kelch13 Markers of Artemisinin Resistance and Low Frequency of a Pfcoronin Mutation in Igombe, Mwanza Region, Tanzania.

Tanzania recently identified partial artemisinin resistance in the Kagera region bordering Rwanda and Uganda, where resistance is established. Monitoring neighboring regions is critical to guide containment strategies. We, therefore, conducted molecular surveillance of Plasmodium falciparum Kelch13 (pfk13) and Plasmodium falciparum actin-binding protein coronin (pfcoronin; P76S) mutations in Igombe in Mwanza region. In a health facility-based cross-sectional study in 2025, P. falciparum DNA from patients with uncomplicated malaria was analyzed using polymerase chain reaction, Sanger sequencing, and allele-specific melting curve assays. Among 121 sequenced isolates, no validated or candidate pfk13 mutations were detected. The nonsynonymous, nonvalidated pfk13 variant N489K occurred in 2.5%. The pfcoronin P76S mutation was observed at low prevalence (3.6%). Despite proximity to Kagera hot spots, validated pfk13 markers have not yet been established in the Mwanza region. The presence of pfcoronin P76S, albeit at low levels, requires careful monitoring. Continued molecular surveillance is essential to support the early detection and containment of emerging artemisinin resistance in Tanzania.