title: Spatio-temporal analysis of the genetic diversity and complexity of Plasmodium falciparum infections in Kedougou, southeastern Senegal.
abstract: Genetic analyses of the malaria parasite population and its temporal and spatial dynamics could provide an assessment of the effectiveness of disease control strategies. The genetic diversity of Plasmodium falciparum has been poorly documented in Senegal, and limited data are available from the Kedougou Region. This study examines the spatial and temporal variation of the genetic diversity and complexity of P. falciparum infections in acute febrile patients in Kedougou, southeastern Senegal. A total of 263 sera from patients presenting with acute febrile illness and attending Kedougou health facilities between July 2009 and July 2013 were obtained from a collection established as part of arbovirus surveillance in Kedougou. Samples identified as P. falciparum by nested PCR were characterized for their genetic diversity and complexity using msp-1 and msp-2 polymorphic markers.
  
  
  
  Samples containing only P. falciparum accounted for 60.83% (160/263) of the examined samples. All three msp-1 allelic families (K1, MAD20 and RO33) and two msp-2 allelic families (FC27 and 3D7) were detected in all villages investigated over the 5-year collection period. The average genotype per allelic family was comparable between villages. Frequencies of msp-1 and msp-2 allelic types showed no correlation with age (Fisher's exact test, P = 0.59) or gender (Fisher's exact test, P = 0.973), and were similarly distributed throughout the 5-year sampling period (Fisher's exact test, P = 0.412) and across villages (Fisher's exact test, P = 0.866). Mean multiplicity of infection (MOI) for both msp-1 and msp-2 was highest in Kedougou village (2.25 and 2.21, respectively) and among younger patients aged ≤ 15 years (2.12 and 2.00, respectively). The mean MOI was highest in 2009 and decreased progressively onward.
  
  
  
  Characterization of the genetic diversity and complexity of P. falciparum infections in Kedougou revealed no spatio-temporal variation in the genetic diversity of P. falciparum isolates. However, mean MOI varied with time of sera collection and decreased over the course of the study (July 2009 to July 2013). This suggests a slow progressive decrease of malaria transmission intensity in Kedougou Region despite the limited impact of preventive and control measures implemented by the National Malaria Control Programme on malaria morbidity and mortality.
authors.affiliation: Institut Pasteur Dakar, Immunology Unit, 36 Avenue Pasteur, BP 220, Dakar, Senegal. mniang@pasteur.sn.
authors.forename: Makhtar
authors.initials: M
authors.lastname: Niang
authors.affiliation: Institut Pasteur Dakar, Immunology Unit, 36 Avenue Pasteur, BP 220, Dakar, Senegal.|Department of Animal Biology, Cheikh Anta Diop University of Dakar, Dakar, Senegal.
authors.forename: Laty G
authors.initials: LG
authors.lastname: Thiam
authors.affiliation: Institut Pasteur Dakar, Biostatistics, Bioinformatics and Modeling Group, 36 Avenue Pasteur, BP 220, Dakar, Senegal.
authors.forename: Cheikh
authors.initials: C
authors.lastname: Loucoubar
authors.affiliation: Institut Pasteur Dakar, Arbovirus and Viral Hemorrhagic Fevers Unit, 36 Avenue Pasteur, BP 220, Dakar, Senegal.
authors.forename: Abdourahmane
authors.initials: A
authors.lastname: Sow
authors.affiliation: Institut Pasteur Dakar, Arbovirus and Viral Hemorrhagic Fevers Unit, 36 Avenue Pasteur, BP 220, Dakar, Senegal.
authors.forename: Bacary D
authors.initials: BD
authors.lastname: Sadio
authors.affiliation: Institut Pasteur Dakar, Medical Entomology Unit, 36 Avenue Pasteur, BP 220, Dakar, Senegal.
authors.forename: Mawlouth
authors.initials: M
authors.lastname: Diallo
authors.affiliation: Institut Pasteur Dakar, Arbovirus and Viral Hemorrhagic Fevers Unit, 36 Avenue Pasteur, BP 220, Dakar, Senegal.
authors.forename: Amadou A
authors.initials: AA
authors.lastname: Sall
authors.affiliation: Institut Pasteur Dakar, Immunology Unit, 36 Avenue Pasteur, BP 220, Dakar, Senegal.
authors.forename: Aissatou
authors.initials: A
authors.lastname: Toure-Balde
mesh_terms: D000483:Alleles; D000953:Antigens, Protozoan / Q000235:genetics; D014644:Genetic Variation; D006801:Humans; D016778:Malaria, Falciparum / Q000469:parasitology*; D020066:Merozoite Surface Protein 1 / Q000235:genetics; D010963:Plasmodium falciparum / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D016133:Polymerase Chain Reaction; D015800:Protozoan Proteins / Q000235:genetics; D012675:Senegal; D017422:Sequence Analysis, DNA; D062211:Spatio-Temporal Analysis
chemical_list: D000953:Antigens, Protozoan; D020066:Merozoite Surface Protein 1; D015800:Protozoan Proteins; C065974:merozoite surface protein 2, Plasmodium
keywords: Diversity; Kedougou; Malaria; Plasmodium falciparum; Transmission