title: Polymorphisms in chloroquine resistance-associated genes in Plasmodium vivax in Ethiopia.
abstract: BACKGROUND
  Evidence for decreasing chloroquine (CQ) efficacy against Plasmodium vivax has been reported from many endemic countries in the world. In Ethiopia, P. vivax accounts for 40% of all malaria cases and CQ is the first-line drug for vivax malaria. Mutations in multidrug resistance 1 (pvmdr-1) and K10 insertion in the pvcrt-o genes have been identified as possible molecular markers of CQ-resistance (CQR) in P. vivax. Despite reports of CQ treatment failures, no data are currently available on the prevalence of molecular markers of P. vivax resistance in Ethiopia. The objective of this study was to determine the prevalence of mutations in the pvmdr-1 and K10 insertion in the pvcrt-o genes.
  
  
  METHODS
  A total of 36 P. vivax clinical isolates were collected from West Arsi district in Ethiopia. Sequencing was used to analyse polymorphisms of the pvcrt-o and pvmdr-1 genes.
  
  
  RESULTS
  Sequencing results of the pvmdr-1 fragment showed the presence of two non-synonymous mutations at positions 976 and 1076. The Y → F change at codon 976 (TAC → TTC) was observed in 21 (75%) of 28 the isolates while the F → L change (at codon 1076), which was due to a single mutation (TTT → CTT), was observed in 100% of the isolates. Of 33 samples successfully amplified for the pvcrt-o, the majority of the isolates (93.9%) were wild type, without K10 insertion.
  
  
  CONCLUSIONS
  High prevalence of mutations in candidate genes conferring CQR in P. vivax was identified. The fact that CQ is still the first-line treatment for vivax malaria, the significance of mutations in the pvcrt-o and pvmdr-1 genes and the clinical response of the patients' to CQ treatment and whether thus an association exists between point mutations of the candidate genes and CQR requires further research in Ethiopia.
authors.affiliation: Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia. lgolassa@gmail.com.|Armauer Hansen Research Institute, Addis Ababa, Ethiopia. lgolassa@gmail.com.
authors.forename: Lemu
authors.initials: L
authors.lastname: Golassa
authors.affiliation: Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia.
authors.forename: Berhanu
authors.initials: B
authors.lastname: Erko
authors.affiliation: Department of Biology, LeTourneau University, Longview, TX, USA.
authors.forename: Frederick N
authors.initials: FN
authors.lastname: Baliraine
authors.affiliation: Armauer Hansen Research Institute, Addis Ababa, Ethiopia.
authors.forename: Abraham
authors.initials: A
authors.lastname: Aseffa
authors.affiliation: Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden.
authors.forename: Göte
authors.initials: G
authors.lastname: Swedberg
mesh_terms: D002738:Chloroquine / Q000494:pharmacology*; D004351:Drug Resistance / Q000235:genetics*; D005002:Ethiopia / Q000453:epidemiology; D017125:Genes, Protozoan / Q000235:genetics; D006801:Humans; D016780:Malaria, Vivax / Q000453:epidemiology / Q000469:parasitology*; D009154:Mutation; D010966:Plasmodium vivax / Q000187:drug effects* / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics
chemical_list: D002738:Chloroquine