title: Evaluation of Plasmodium vivax genotyping markers for molecular monitoring in clinical trials.
abstract: BACKGROUND
  Many antimalarial interventions are accompanied by molecular monitoring of parasite infections, and a number of molecular typing techniques based on different polymorphic marker genes are used. Here, we describe a genotyping technique that provides a fast and precise approach to study Plasmodium vivax infection dynamics during circumstances in which individual clones must be followed over time. The method was tested with samples from an in vivo drug efficacy study.
  
  
  METHODS
  The sizes of polymerase chain reaction fragments were evaluated by capillary electrophoresis to determine the extent of size polymorphism for 9 potential genetic markers (5 genes of merozoite surface proteins [msp] and 4 microsatellites) in 93-108 P. vivax-positive blood samples from 3 villages in Papua New Guinea.
  
  
  RESULTS
  The microsatellites MS16 and Pv3.27 showed the greatest diversity in the study area, with 66 and 31 different alleles, respectively, followed by 2 fragments of msp1 and 2 other microsatellites. msp3alpha, msp4, and msp5 revealed limited polymorphism.
  
  
  CONCLUSIONS
  Even for the most diverse markers, the highest allelic frequencies reached 6% (MS16) or 13% (Pv3.27). To reduce the theoretical probability of superinfection with parasites that have the same haplotype as that detected at baseline, we propose to combine at least 2 markers for genotyping individual P. vivax infections.
authors.affiliation: Swiss Tropical Institute, Basel, Switzerland.
authors.forename: Cristian
authors.initials: C
authors.lastname: Koepfli
authors.forename: Ivo
authors.initials: I
authors.lastname: Mueller
authors.forename: Jutta
authors.initials: J
authors.lastname: Marfurt
authors.forename: Mary
authors.initials: M
authors.lastname: Goroti
authors.forename: Albert
authors.initials: A
authors.lastname: Sie
authors.forename: Olive
authors.initials: O
authors.lastname: Oa
authors.forename: Blaise
authors.initials: B
authors.lastname: Genton
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Beck
authors.forename: Ingrid
authors.initials: I
authors.lastname: Felger
mesh_terms: D000483:Alleles; D000818:Animals; D000962:Antimalarials / Q000627:therapeutic use*; D004351:Drug Resistance / Q000235:genetics; D005787:Gene Frequency; D005819:Genetic Markers; D014644:Genetic Variation; D005838:Genotype; D006239:Haplotypes; D016780:Malaria, Vivax / Q000188:drug therapy / Q000453:epidemiology / Q000469:parasitology*; D018895:Microsatellite Repeats; D010219:Papua New Guinea / Q000453:epidemiology; D010966:Plasmodium vivax / Q000145:classification / Q000187:drug effects / Q000235:genetics*; D015800:Protozoan Proteins / Q000235:genetics
chemical_list: D000962:Antimalarials; D005819:Genetic Markers; D015800:Protozoan Proteins