Sentinel surveillance of the WHO-Validated Pfkelch13 C580Y Artemisinin Resistance Marker in Plasmodium falciparum Isolates from Bangui, Central African Republic

Abstract

Background: Artemisinin-based combination therapies (ACTs) are the cornerstone of malaria treatment. However, partial artemisinin resistance associated with mutations in the Plasmodium falciparum Pfkelch13 propeller domain threatens malaria control efforts. The C580Y substitution is the principal World Health Organization (WHO) validated molecular marker for resistance surveillance. While validated Pfkelch13 mutations have recently emerged in East Africa, data from Central Africa remain scarce. This study assessed the prevalence of the C580Y mutation in P. falciparum isolates collected in Bangui, Central African Republic (CAR), in 2025. Methods: A cross-sectional molecular surveillance study was conducted in November 2025 in Bangui. Blood samples from 399 microscopy-confirmed malaria patients were collected as dried blood spots. Parasite DNA was extracted using the Chelex-100 method. Species identification was performed by nested PCR targeting the 18S rRNA gene. P. falciparum-positive samples underwent nested PCR amplification of the pfk13 propeller domain, followed by PCR–restriction fragment length polymorphism (PCR-RFLP) to detect the C580Y mutation. Exact 95% binomial confidence intervals were calculated. Results: Among 399 patients (mean age 27.8 ± 11.9 years; 52.6% male), 99.75% harbored P. falciparum. Successful Pfkelch13 amplification was achieved in 368 of 398 isolates (92.5%). No C580Y mutation was detected (0/368; 0%; 95% CI: 0.00–0.81%), indicating that its prevalence in Bangui is likely below 1%. Conclusion: The absence of the WHO-validated C580Y marker in 2025 suggests preserved molecular susceptibility of Plasmodium falciparum to artemisinin in CAR. Continued genomic surveillance remains essential to detect potential emergence or importation of resistant lineages.