ABSTRACT
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.
Subject(s)
Carrier State/parasitology , Genetic Variation , Genotype , Malaria, Falciparum/parasitology , Plasmodium falciparum/classification , Plasmodium falciparum/genetics , Adolescent , Antigens, Protozoan/genetics , Carrier State/epidemiology , Child , Child, Preschool , Cote d'Ivoire/epidemiology , Cross-Sectional Studies , Female , Genotyping Techniques , Humans , Malaria, Falciparum/epidemiology , Male , Merozoite Surface Protein 1/genetics , Plasmodium falciparum/isolation & purification , Protozoan Proteins/genetics , Rural Population , Schools , Seasons , Urban PopulationABSTRACT
Despite efforts to eliminate it, malaria remains a major public health concern, particularly in Côte d'Ivoire. Chloroquine (CQ) was one of the first drugs used for its treatment, but was officially withdrawn from the market in 2007 following reports of high levels of chloroquine resistance. The present study was carried out after the withdrawal of CQ and provides an update on the rates of CQ resistance in Côte d'Ivoire. Samples were collected between September 2013 and March 2014 in Abidjan and from January to May 2016 in Abengourou and San Pedro through cross-sectional studies. Parasitemia was assessed by microscopy, and single nucleotide polymorphism in the Pfcrt (codon 76) gene was analyzed by nested PCR and restriction fragment length polymorphism. A total of 343 samples were analyzed: 119, 106 and 118 were from Abidjan, Abengourou, and San Pedro, respectively. The sex ratio of patients was 0.92. The mean age of patients enrolled was 9.6 years (SD = 10.8). The geometric mean of parasite density was 21,337 parasites/µL (SD = 49,508; range, 2,000-200,000). Molecular analysis revealed 57 K76T mutants (16.6%): 33, 9, and 15 in Abidjan, Abengourou and in San Pedro, respectively. Most of these were found in patients aged ≤15 years (42/57) who had parasitemia greater than 10,000 parasites/µL (40/57). This is the first study conducted in Côte d'Ivoire reporting a decline in Pfcrt K76T mutation rate. Thus, our results indicate the importance of following up on the observed trend also at a national level.
