title: Genetic diversity among Plasmodium vivax isolates along the Thai-Myanmar border of Thailand.
abstract: BACKGROUND
  Knowledge of the population genetics and transmission dynamics of Plasmodium vivax is crucial in predicting the emergence of drug resistance, relapse pattern and novel parasite phenotypes, all of which are relevant to the control of vivax infections. The aim of this study was to analyse changes in the genetic diversity of P. vivax genes from field isolates collected at different times along the Thai-Myanmar border.
  
  
  METHODS
  Two hundred and fifty-four P. vivax isolates collected during two periods 10 years apart along the Thai-Myanmar border were analysed. The parasites were genotyped by nested-PCR and PCR-RFLP targeting selected polymorphic loci of Pvmsp1, Pvmsp3α and Pvcsp genes.
  
  
  RESULTS
  The total number of distinguishable allelic variants observed for Pvcsp, Pvmsp1, and Pvmsp3α was 17, 7 and 3, respectively. High genetic diversity was observed for Pvcsp (H E = 0.846) and Pvmsp1 (H E = 0.709). Of the 254 isolates, 4.3 and 14.6 % harboured mixed Pvmsp1 and Pvcsp genotypes with a mean multiplicity of infection (MOI) of 1.06 and 1.15, respectively. The overall frequency of multiple genotypes was 16.9 %. When the frequencies of allelic variants of each gene during the two distinct periods were analysed, significant differences were noted for Pvmsp1 (P = 0.018) and the Pvcsp (P = 0.033) allelic variants.
  
  
  CONCLUSIONS
  Despite the low malaria transmission levels in Thailand, P. vivax population exhibit a relatively high degree of genetic diversity along the Thai-Myanmar border of Thailand, in particular for Pvmsp1 and Pvcsp, with indication of geographic and temporal variation in frequencies for some variants. These results are of relevance to monitoring the emergence of drug resistance and to the elaboration of measures to control vivax malaria.
authors: Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Road, Bangkok, 10400, Thailand. sarunya.man@student.mahidol.ac.th.
authors: Sarunya
authors: S
authors: Maneerattanasak
authors: Department of Immunology and Medicine, Armed Forces Research Institute of Medical Science-United States Army Military Component, Bangkok, Thailand. panitag@afrims.org.
authors: Panita
authors: P
authors: Gosi
authors: Clinical Malaria Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. srivicha.kru@mahidol.ac.th.
authors: Srivicha
authors: S
authors: Krudsood
authors: Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Road, Bangkok, 10400, Thailand. jarinee.pan@mahidol.ac.th.
authors: Jarinee
authors: J
authors: Tongshoob
authors: Department of Immunology and Medicine, Armed Forces Research Institute of Medical Science-United States Army Military Component, Bangkok, Thailand. charlotte.a.lanteri.mil@mail.mil.
authors: Charlotte A
authors: CA
authors: Lanteri
authors: UPMC UMRS CR7, Sorbonne Universités, UPMC Univ Paris 06, 75005, Paris, France. georges.snounou@upmc.fr.|Institut National de la Santé et de la Recherche Médicale (Inserm) U1135 - Centre National de la Recherche Scientifique (CNRS) ERL 8255, Centre d'Immunologie et de Maladies Infectieuses (CIMI) - Paris, 75013, Paris, France. georges.snounou@upmc.fr.
authors: Georges
authors: G
authors: Snounou
authors: Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Road, Bangkok, 10400, Thailand. srisin.khu@mahidol.ac.th.|Center for Emerging and Neglected Infectious Diseases, Mahidol University, Bangkok, Thailand. srisin.khu@mahidol.ac.th.
authors: Srisin
authors: S
authors: Khusmith
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D014644:Genetic Variation / Q000235:genetics; D005838:Genotype; D006801:Humans; D016780:Malaria, Vivax / Q000469:parasitology; D008297:Male; D008875:Middle Aged; D010966:Plasmodium vivax / Q000145:classification / Q000235:genetics*; D016133:Polymerase Chain Reaction; D015800:Protozoan Proteins / Q000235:genetics*; D013785:Thailand; D055815:Young Adult
chemical_list: D015800:Protozoan Proteins