Molecular Epidemiology of Plasmodium falciparum Kelch13 Mutations and Artemisinin Partial Resistance Markers in Anambra State

Artemisinin partial resistance in Plasmodium falciparum, mediated primarily by mutations in the kelch13 (K13) propeller domain, has been confirmed in East Africa and raises urgent surveillance questions for West African malaria programs. This molecular epidemiological study investigated the prevalence of K13 mutations and validated artemisinin resistance markers in P. falciparum isolates from malaria patients in Onitsha and Awka, Anambra State, in the South East geopolitical zone of Nigeria. Blood samples from 200 confirmed P. falciparum malaria cases were dried on filter paper. DNA was extracted and nested PCR amplification of the K13 propeller domain was performed, followed by Sanger sequencing. The pfcoronin, pfkelch13, and plasmepsin 2-3 loci were also characterized. No validated WHO-defined K13 resistance mutations (R539T, C580Y, I543T) were detected. However, 11.5 percent of isolates carried the A578S polymorphism, a mutation of uncertain clinical significance present in African populations. pfcoronin mutations were detected in 6 percent of isolates. Therapeutic efficacy monitoring conducted concurrently showed day-3 positivity rates of 8.6 percent, warranting continued monitoring. These findings provide important baseline data on artemisinin resistance markers in Anambra State and support continued molecular surveillance to provide early warning of emerging artemisinin partial resistance within Nigeria's malaria control program. Keywords: Plasmodium falciparum, kelch13, artemisinin resistance, molecular surveillance, Anambra.