Asymptomatic carriers of Plasmodium are considered a reservoir of the parasite in humans. Therefore, in order to be effective, new malaria elimination strategies must take these targets into account. The aim of this study was to analyse genetic diversity of Plasmodium falciparum among schoolchildren in three epidemiological areas in Côte d'Ivoire. This was a crosssectional study carried out from May 2015 to April 2016 in a primary school in rural and urban areas of San Pedro, Grand-Bassam and Abengourou, during the rainy season and the dry season. A total of 282 Plasmodium falciparum isolates were genotyped using Nested PCR of Pfmsp1 and Pfmsp2 genes. The overall frequency of K1, Mad20 and RO33 alleles was 81.6%, 53.4% and 57% for Pfmsp1 respectively. For Pfmsp2, this frequency was 84.3% and 72.2% for 3D7 and FC27. K1, Mad20 and FC27 Frequencies were significantly higher in Abengourou compared to other sites. Overall, the frequency of MIs was significantly higher in Abengourou for Pfmsp1 and Pfmsp2. However, Mad20 and RO33 alleles were significantly higher in the rainy season. No significant difference was observed between Pfmsp2 alleles in both seasons. Frequency of the 3D7 allele was significantly higher in symptomatic patients. MIs and COI increased with parasitemia for Pfmsp1and Pfmsp2. The data can be added to that available for monitoring and control of P. falciparum malaria. Further studies combining the entomological inoculation rate and the genetic diversity of P. falciparum will allow us to shed light on our understanding of the epidemiology of this parasite.

Malaria is a major public health problem, particularly in the tropical regions of America, Africa and Asia. Plasmodium falciparum is not only the most widespread but also the most deadly species. The share of Plasmodium infestations caused by the other species (P. ovale and P. malariae) is clearly underestimated. General objective was to determine the molecular epidemiology of plasmodial infestations due to P. malariae and P. ovale in Côte d'Ivoire. This is a cross-sectional study which took place from February to March 2021 at the Centre de Recherche et de Lutte contre le Paludisme (CRLP) of the Institut National de Santé Publique (INSP). The collection of samples took place from May 2015 to April in different malaria epidemiological facies in Côte d'Ivoire. Analysis of the collected samples was performed. In each patient, we collected blood by venipuncture at the elbow on EDTA tubes. These samples were used to make confetti on Wathman paper for the molecular diagnosis of malaria. Molecular diagnosis as well as differential diagnosis of plasmodial species using the nested PCR technique. A total of 360 samples were tested with a success rate of 72.5% (261 out of 360). The sex ratio was 0.84. The overall plasmodic index was 72.5%. The specific index was 77.4%; 1.5% and 0% for P. falciparum, P. malariae and P. ovale in mono-infestation, respectively. There was also 15% P. falciparum and P. malariae co-infestation, 3.4% P. falciparum and P. ovale co-infestation and 2.3% P. falciparum, P. malariae and P. ovale triple-infestation. After exclusion of P. falciparum monoinfestation cases, 59 samples were finally retained to evaluate the molecular epidemiology of non-falciparum Plasmodium infestations. Typing of Plasmodium ovale subspecies showed a clear predominance of Plasmodium ovale curtisi (81.2% of cases). Plasmodium falciparum remains the most prevalent malaria species in Côte d'Ivoire, but P. malariae and P. ovale are endemic at a low rate. The elimination of malaria requires a better understanding of the specific epidemiological characteristics of P. malariae and P. ovale with a particular emphasis on the identification of asymptomatic carriers.

One of the major obstacles to malaria elimination is the decreased susceptibility of Plasmodium falciparum to most antimalarial drugs. This study was focused on the prevalence of molecular markers linked to P. falciparum resistance to antimalarial drugs at different sites in Côte d'Ivoire. Samples were collected from 2013 to 2016 from asymptomatic and symptomatic subjects in Abengourou, Abidjan, Grand Bassam, and San Pedro. A total of 704 participants were enrolled. All samples were analyzed for pfk13 gene, while 344 samples were examined for pfmdr1. Overall, the success rate of molecular tests was 98.8% (340/344), 99.1% (341/344), and 94.3% (664/704) for pfmdr1 N86Y, pfmdr1 Y184F, and pfk13 genes respectively. Molecular analysis revealed twenty (5.9%; 20/340) and 219 (64.2%; 219/341) mutant alleles for pfmdr1 86Y and pfmdr1 184F, respectively. Twenty-nine cases of mutations in pfk13 gene (4.4%; 29/664) with 2.7% (18/664) of non-synonymous mutations was found. None of the mutations previously described in South East Asia (SEA) involved in P. falciparum resistance to artemisinin derivatives were reported in this study. According to year of collection, a decrease of the prevalence of pfk13 mutation (from 3.6–1.8%) and pfmdr1 N86Y mutation (from 8.5–4.5%) was noticed while an increase of mutant allele of pfmdr1 Y184F proportion (from 39.8–66.4%) was found. Comparing to previous studies in the country, an increase in lumefantrine tolerance of P. falciparum strains were noticed. The results of this study demonstrate the importance of establishing a strong system for molecular surveillance of malaria in Côte d’Ivoire.

Background Malaria is a major public health problem, particularly in the tropical regions of America, Africa and Asia. Plasmodium falciparum is not only the most widespread but also the most deadly species. The share of Plasmodium infections caused by the other species (Plasmodium ovale and Plasmodium malariae) is clearly underestimated. The objective of the study was to determine the molecular epidemiology of plasmodial infection due to P. malariae and P. ovale in Côte d'Ivoire. Methods The study was cross-sectional. The study participants were recruited from Abengourou, San Pedro and Grand-Bassam. Sample collection took place from May 2015 to April 2016. Questionnaires were administered and filter paper blood samples were collected for parasite DNA extraction. The molecular analysis was carried out from February to March 2021. A nested PCR was used for species diagnosis. The data was presented in frequencies and proportions. Results A total of 360 patients were recruited, including 179 men (49,7%) for 181 women (50,3%). The overall Plasmodium positive rate was 72.5% (261/360). The specific index was 77.4% and 1.5% for P. falciparum and P. malariae in mono-infection, respectively. There was also 15% P. falciparum and P. malariae co-infection, 3.4% P. falciparum and P. ovale co-infection and 2.3% P. falciparum, P. malariae and P. ovale triple-infection. Typing of P. ovale subspecies showed a significant predominance of P. ovale curtisi (81.2% of cases). Conclusion Plasmodium falciparum remains the most prevalent malaria species in Côte d'Ivoire, but P. malariae and P. ovale are also endemic mostly in co-infection. Malaria elimination requires a better understanding of the specific epidemiological characteristics of P. malariae and P. ovale with a particular emphasis on the identification of asymptomatic carriers.