Molecular Epidemiology of Plasmodium falciparum Drug Resistance Markers in Malaria Isolates from North West and South West Nigeria: A Comparative Analysis

The molecular surveillance of drug resistance markers in Plasmodium falciparum provides critical data for updating national malaria treatment policies and predicting the therapeutic efficacy of artemisinin-based combination therapies. This study compared the prevalence of key drug resistance markers in P. falciparum isolates from malaria-endemic communities in Kano State and Oyo State, representing North West and South West Nigeria respectively. Blood samples from 400 microscopically confirmed P. falciparum malaria patients were collected across both sites. DNA extraction was performed using the QIAamp DNA Blood Mini Kit, and resistance-associated mutations in the Pfkelch13, Pfcrt, and Pfmdr1 genes were detected by nested PCR and Sanger sequencing. Pfcrt K76T mutation prevalence was 38.4% in North West versus 29.6% in South West samples. Pfmdr1 N86Y was detected in 31.7% and 24.3% respectively. No Pfkelch13 validated resistance mutations were found, suggesting artemisinin susceptibility in both zones. However, several non-validated Pfkelch13 polymorphisms of undetermined significance were identified. Haplotype analysis revealed distinct geographic clustering of resistance allele combinations between zones. The absence of validated artemisinin resistance mutations supports continued use of ACTs in both regions, but the significant chloroquine resistance marker prevalence justifies the continued suspension of chloroquine monotherapy. The findings contribute empirical data for national treatment guideline review and recommend sustained molecular resistance surveillance across all six geopolitical zones in Nigeria. Keywords: Plasmodium falciparum, drug resistance, Pfkelch13, molecular surveillance, artemisinin