Increase of Plasmodium falciparum parasites carrying lumefantrine-tolerance molecular markers and lack of South East Asian pfk13 artemisinin-resistance mutations in samples collected from 2013 to 2016 in Côte d'Ivoire.

One of the major obstacles to malaria elimination in the world is the resistance in Plasmodium falciparum to most antimalarial drugs. This study aimed to estimate the prevalence of molecular markers of antimalarial drugs resistance 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 aged between 1 year and 65 years (Mean age: 9 years ± 7.7) were enrolled. All the dried filter paper blood spots were genotyped by sequencing. Plasmodium falciparum kelch propeller domain 13 (pfk13) gene were analyzed for all the samples, while 344 samples were examined for Plasmodium falciparum multi-drug resistance 1 (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 184 F, respectively. Twenty-nine 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 observed in this study. According to year of collection, a decrease of the prevalence of pfk13 mutation (from 3.6 to 1.8%) and pfmdr1 N86Y mutation (from 8.5 to 4.5%) and an increase of mutant allele of pfmdr1 Y184F proportion (from 39.8 to 66.4%) were found. Comparing to previous studies in the country, this study showed an increase in lumefantrine tolerance of P. falciparum strains. This demonstrates the importance of establishing a strong system for molecular surveillance of malaria in Côte d'Ivoire.

Meta-Analysis of Data from Four Clinical Trials in the Ivory Coast Assessing the Efficacy of Two Artemisinin-Based Combination Therapies (Artesunate-Amodiaquine and Artemether-Lumefantrine) between 2009 and 2016.

The combinations of artemether-lumefantrine (AL) and artesunate-amodiaquine (ASAQ) are used as first-line treatments for uncomplicated malaria in the Ivory Coast. Different studies document the efficacy of two artemisinin-based combination therapies (ACTs) (AL and ASAQ) in the Ivory Coast. However, there is no meta-analysis examining the data set of these studies. The purpose of this work was to determine the prevalence of malaria treatment failure cases in randomized control trials with two artemisinin-based combination therapies (AL versus ASAQ) in the Ivory Coast between 2009 to 2016. This study is a meta-analysis of data from the results of four previous multicenter, open-label, randomized clinical trial studies evaluating the clinical and parasitological efficacy of artemether-lumefantrine and artesunate-amodiaquine conducted between 2009 and 2016 following World Health Organization (WHO) protocol at sentinel sites in the Ivory Coast. These drug efficacy data collected between 2009 and 2016 were analyzed. During these studies, to distinguish between recrudescence and new infection, molecular genotyping of genes encoding merozoite surface protein 1 and 2 was carried out using nested polymerase chain reaction (PCR). A total of 1575 patients enrolled in the four studies, including 768 in the AL arm and 762 in the ASAQ arm, which were fully followed either for 28 days or 42 days according to WHO protocol. The adequate clinical and parasitological response (ACPR) was higher than 95% in the two groups (intention to treat (ITT): AL = 96.59% and ASAQ = 96.81; Per Protocol (PP): AL = 99.48% and ASAQ = 99.61%) after PCR correction at day 28. Aggregate data analysis (2009-2016) showed that at day 28, the proportions of patients with recurrent infection was higher in the AL group (ITT: 3.79%, PP: 3.9%) than in the ASAQ group (ITT: 2.17%, PP: 2.23%). After PCR correction, most treatment failures were classified as new infections (AL group (ITT: 0.13%, PP: 0.13%); ASAQ group (ITT: 0.39%, PP: 0.39%). The recrudescent infections rate was high, at 0.39% compared to 0.13% for ASAQ and AL, respectively, for both ITT and PP, no significant difference. However, the Kaplan-Meier curve of cumulative treatment success showed a significant difference between the two groups after PCR from 2012-2013 (p = 0.032). Overall, ASAQ and AL have been shown to be effective drugs for the treatment of uncomplicated P. falciparum malaria in the study areas, 14 years after deployment of these drugs.

Effectiveness of intermittent preventive treatment with Sulfadoxine-Pyrimethamine in pregnant women in San Pedro, Côte D'Ivoire.

Malaria remains a major public health issue for pregnant women. Côte d'Ivoire has adopted a series of measures aimed at combatting this plague, and these measures include administering Sulfadoxine-Pyrimethamine (SP) as an intermittent preventive treatment to pregnant women in the second and third terms.This cross-sectional study included a parturient population after informed written consent. We recruited women from the Terre Rouge maternity ward and the labor room of the Regional Medical Center of San-Pedro. Plasmodial DNA (desoxyribo nucleic acid) was extracted from Whatman filter papers with dried blood samples prepared from the venous, placental, and cord blood, utilizing Chelex 100. The extracts obtained were amplified by nested PCR.In all, 197 women were included, with an average age of 27-year-old (sd = 6.7 years old). The rates of the placental, venous and cord blood infections were 16, 2%, 15, 2% and 3, 6%, respectively. The women who took three doses of ITP were less infected at the cord (3, 2%), placental (10,6%) and venous level (13,8%). A statistically significant relationship between the number of doses and the rate of placental infection was established (p = 0.042). IPT reduces plasmodial infestation at the placental (OR = 0.4; CI = [0.2-1]), cord (OR = 0.8; CI = [0.2-3.7]) and venous (OR = 0.8; CI = [0.6-2.3]) level.In conclusion, the low frequency of placental, venous, and cord infestation in pregnant women who consistently followed a preventive treatment strategy clearly showed the efficiency of IPT against malaria during pregnancy.

Dynamics of Plasmodium falciparum genetic diversity among asymptomatic and symptomatic children in three epidemiological areas in Cote d'Ivoire.

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 cross-sectional 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.

Efficacy and tolerability of artesunate-amodiaquine versus artemether-lumefantrine in the treatment of uncomplicated Plasmodium falciparum malaria at two sentinel sites across Côte d'Ivore

Malaria remains a major public health problem in Côte d'Ivoire. The aim of this study is to compare the efficacy and tolerability of artesunate-amodiaquine (ASAQ) versus artemether-lumefantrine (AL) for the treatment of uncomplicated malaria, at two malaria surveillance sites in Côte d'Ivoire. The World Health Organization 2003 protocol was used for this multicenter open randomized clinical trial with a 42-day follow-up. We recruited 240 patients (120 per arm), of whom 114 (ASAQ group) and 112 (AL group) were fully followed-up. According to intention-to-treat statistical analysis, PCR-corrected cure rates for ASAQ and AL treatments were 95.8% and 92.5% on day 28, and 95% and 92.5% on day 42, respectively. Based on per-protocol statistical analysis, ASAQ and AL treatment rates reached 100% and 99.1%, respectively, on day 28 and remained the same on day 42. Overall, both drugs were well-tolerated at the clinical and biological level. This study shows that ASAQ and AL are still effective and well-tolerated. Accordingly, they can continue being used to treat uncomplicated malaria in Côte d'Ivoire. However, monitoring of their efficacy should remain a priority for health authorities.