title: Population Genetics of Plasmodium vivax in Four Rural Communities in Central Vietnam.
abstract: BACKGROUND
  The burden of malaria in Vietnam has drastically reduced, prompting the National Malaria Control Program to officially engage in elimination efforts. Plasmodium vivax is becoming increasingly prevalent, remaining a major problem in the country's central and southern provinces. A better understanding of P. vivax genetic diversity and structure of local parasite populations will provide baseline data for the evaluation and improvement of current efforts for control and elimination. The aim of this study was to examine the population genetics and structure of P. vivax isolates from four communities in Tra Leng commune, Nam Tra My district in Quang Nam, Central Vietnam.
  
  
  RESULTS
  P. vivax mono infections collected from 234 individuals between April 2009 and December 2010 were successfully analyzed using a panel of 14 microsatellite markers. Isolates displayed moderate genetic diversity (He = 0.68), with no significant differences between study communities. Polyclonal infections were frequent (71.4%) with a mean multiplicity of infection of 1.91 isolates/person. Low but significant genetic differentiation (FST value from -0.05 to 0.18) was observed between the community across the river and the other communities. Strong linkage disequilibrium ([Formula: see text] = 0.113, p < 0.001) was detected across all communities, suggesting gene flow within and among them. Using multiple approaches, 101 haplotypes were grouped into two genetic clusters, while 60.4% of haplotypes were admixed.
  
  
  CONCLUSIONS
  In this area of Central Vietnam, where malaria transmission has decreased significantly over the past decade, there was moderate genetic diversity and high occurrence of polyclonal infections. Local human populations have frequent social and economic interactions that facilitate gene flow and inbreeding among parasite populations, while decreasing population structure. Findings provide important information on parasites populations circulating in the study area and are relevant to current malaria elimination efforts.
authors.affiliation: National Institute of Malariology, Parasitology and Entomology (NIMPE), Hanoi, Vietnam.|Institute of Tropical Medicine (ITM), Antwerp, Belgium.|International Health Unit, Faculty of Medicine, University of Antwerp, Belgium.
authors.forename: Nguyen Van
authors.initials: NV
authors.lastname: Hong
authors.affiliation: International Health Unit, Faculty of Medicine, University of Antwerp, Belgium.
authors.forename: Christopher
authors.initials: C
authors.lastname: Delgado-Ratto
authors.affiliation: National Institute of Malariology, Parasitology and Entomology (NIMPE), Hanoi, Vietnam.
authors.forename: Pham Vinh
authors.initials: PV
authors.lastname: Thanh
authors.affiliation: Institute of Tropical Medicine (ITM), Antwerp, Belgium.
authors.forename: Peter
authors.initials: P
authors.lastname: Van den Eede
authors.affiliation: Institute of Tropical Medicine (ITM), Antwerp, Belgium.
authors.forename: Pieter
authors.initials: P
authors.lastname: Guetens
authors.affiliation: National Institute of Malariology, Parasitology and Entomology (NIMPE), Hanoi, Vietnam.
authors.forename: Nguyen Thi Huong
authors.initials: NT
authors.lastname: Binh
authors.affiliation: National Institute of Malariology, Parasitology and Entomology (NIMPE), Hanoi, Vietnam.
authors.forename: Bui Quang
authors.initials: BQ
authors.lastname: Phuc
authors.affiliation: National Institute of Malariology, Parasitology and Entomology (NIMPE), Hanoi, Vietnam.
authors.forename: Tran Thanh
authors.initials: TT
authors.lastname: Duong
authors.affiliation: International Health Unit, Faculty of Medicine, University of Antwerp, Belgium.
authors.forename: Jean Pierre
authors.initials: JP
authors.lastname: Van Geertruyden
authors.affiliation: Institute of Tropical Medicine (ITM), Antwerp, Belgium.|Medical Research Council Unit (MRC Unit), Fajara, The Gambia.
authors.forename: Umberto
authors.initials: U
authors.lastname: D'Alessandro
authors.affiliation: Institute of Tropical Medicine (ITM), Antwerp, Belgium.
authors.forename: Annette
authors.initials: A
authors.lastname: Erhart
authors.affiliation: Institute of Tropical Medicine (ITM), Antwerp, Belgium.
authors.forename: Anna
authors.initials: A
authors.lastname: Rosanas-Urgell
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D016780:Malaria, Vivax / Q000453:epidemiology / Q000469:parasitology*; D008297:Male; D018895:Microsatellite Repeats; D008969:Molecular Sequence Data; D010802:Phylogeny; D010966:Plasmodium vivax / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D012424:Rural Population; D014744:Vietnam / Q000453:epidemiology; D055815:Young Adult