title: Molecular assessment of Plasmodium falciparum resistance to antimalarial drugs in China.
abstract: OBJECTIVE
  In China, Chloroquine (CQ) and sulfadoxine-pyrimethamine (SP) were abandoned for the treatment of falciparum malaria 20 years ago due to resistance. Subsequent field studies showed a trend of declining CQ and SP resistance in the country. The main purpose of this study was to analyse the molecular markers of antimalarial resistance and thereby to assess the possibility of reintroduction of CQ or SP for falciparum malaria treatment.
  
  
  METHODS
  Plasmodium falciparum field isolates were collected in 2006-2007 from Hainan and Yunnan provinces, China. Nested PCR-sequencing assays were applied to analyse the SNPs in four genes: P. falciparum chloroquine resistance transporter (pfcrt) gene, multi-drug resistance 1 (pfmdr1) gene, dihydrofolate reductase (dhfr) gene and dihydropteroate synthetase (dhps) gene.
  
  
  RESULTS
  We found the widespread presence of point mutations in the dhfr and dhps genes which are associated with SP treatment failure. The molecular analyses also showed the fairly high prevalence of point mutation in the pfcrt gene which is linked to CQ resistance.
  
  
  CONCLUSIONS
  The results of the present study indicate that CQ and SP should not be reintroduced for falciparum malaria treatment in the near future in China.
authors.affiliation: National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, WHO Collaborating Center for Malaria, Schistosomiasis and Filariasis, Shanghai 200025, China.
authors.forename: G Q
authors.initials: GQ
authors.lastname: Zhang
authors.forename: Y Y
authors.initials: YY
authors.lastname: Guan
authors.forename: B
authors.initials: B
authors.lastname: Zheng
authors.forename: S
authors.initials: S
authors.lastname: Wu
authors.forename: L H
authors.initials: LH
authors.lastname: Tang
mesh_terms: D000818:Animals; D000962:Antimalarials / Q000627:therapeutic use*; D002681:China; D002738:Chloroquine / Q000627:therapeutic use; D018432:Drug Resistance, Multiple / Q000235:genetics*; D006801:Humans; D016778:Malaria, Falciparum / Q000188:drug therapy; D026901:Membrane Transport Proteins / Q000187:drug effects / Q000235:genetics*; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics*; D010963:Plasmodium falciparum / Q000187:drug effects* / Q000235:genetics; D017354:Point Mutation / Q000235:genetics*; D016133:Polymerase Chain Reaction; D015800:Protozoan Proteins / Q000187:drug effects / Q000235:genetics*; D017422:Sequence Analysis, DNA
chemical_list: D000962:Antimalarials; D002738:Chloroquine; D026901:Membrane Transport Proteins; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D015800:Protozoan Proteins; C513498:Mdr1 protein, Plasmodium falciparum; C416369:PfCRT protein, Plasmodium falciparum