Re-Emerging Chloroquine Sensitivity of Plasmodium falciparum in Côte d'Ivoire: Analysis of pfcrt Gene Polymorphism in Two Health Districts

Background and Objective: Malaria is one of the main causes of morbidity and mortality in the world, particularly in endemic areas. Its management is hampered by the resistance of Plasmodium falciparumto almost all anti-malarial drugs. Mutations in the pfcrt (Plasmodium falciparum Chloroquine Resistance Transporter) gene are associated with Plasmodium falciparum resistance to chloroquine (CQ), and more specifically, mutations at loci 72 to 76 located in the second exon of the gene. This study aims to explore the return of Plasmodium falciparum’s sensitivity to chloroquine in two health districts of Southern Côte d'Ivoire through pfcrt gene polymorphisms. Materials and Methods: After obtaining informed consent, blood samples were collected from patients of all sexes and ages with uncomplicated P. falciparummalaria at Dabou General Hospital and Anonkoua-Kouté Health Centre, located in the South of Côte d'Ivoire, in the Dabou and Abidjan 1 health districts, respectively. Plamodium falciparumgenomic DNA was extracted and amplified by nested-PCR using primers specific for the pfcrtgene. Amplification products were sequenced using the Sanger method at Eurofins Genomics. Key codons (72, 73, 74, 75, and 76), molecular markers of P. falciparumresistance to chloroquine, were analyzed. Data were analyzed in R using the χ² test to compare pfcrt allele and genotype prevalences, with significance set at p<0.05. Results: A total of 112 out of 140 DNA fragments (80%) were successfully sequenced from two sites in Southern Côte d'Ivoire. Analysis of pfcrt codons 72-76 revealed high prevalences of wild-type alleles, with the CVMNK haplotype (chloroquine-sensitive) present in 78.6% of samples. Mutant alleles were rare, and no significant differences were found between the two sites (p>0.05). Conclusion: Nearly twenty years after chloroquine was abandoned as a treatment for uncomplicated malaria in Côte d'Ivoire, the proportion of parasites sensitive to this antimalarial appears to be increasing in the south of the country, particularly in the health districts of Dabou and Abidjan 1.