title: Molecular determination of antifolate resistance associated point mutations in Plasmodium falciparum dihydrofolate reductase (dhfr) and dihydropteroate synthetase (dhps) genes among the field samples in Arunachal Pradesh.
abstract: OBJECTIVE
  Antimalarial resistance in P. falciparum malaria parasite creates a serious obstacle in malaria control programme. Keeping this in mind, in the present study antifolate resistance associated point mutations in P. falciparum dihydrofolate reductase (Pfdhfr) and dihydropteroate synthetase (Pfdhps) genes among the field samples in Arunachal Pradesh were determined.
  
  
  METHODS
  Blood samples were collected from 145 suspected malaria patients/healthy control subjects in malarious areas of Lohit and Changlang districts of Arunachal Pradesh, India during January 2012 to December 2013.
  
  
  RESULTS
  In microscopic slide examination, 51.03% (74/145) were found malaria positive. Plasmodium falciparum mono-infection was observed in 62.16% (46/74) of total malaria positive cases. Polymerase chain reaction (PCR) was employed in all the P. falciparum positive samples for detection of 648 bp of Pfdhfr and 710 bp of Pfdhps genes. All the amplified products were analysed for detection of single nucleotide polymorphisms in dhfr and dhps genes. A total of four different genotypes of Pfdhfr gene were observed, of which double mutant allele ANRNI was mostly prevalent and it was found in 65.22% (30/46) cases. Likewise, four different haplotypes of Pfdhps gene were detected, of which triple mutant allele AGEAA shares 69.57% (32/46) followed by other haplotypes. In Pfdhfr-Pfdhps two locus mutations analysis, two isolates in Changlang district had shown quintuple mutant haplotype AIRNL-AGEAA, likely to be associated with treatment failure. The P. falciparum two locus dhfr-dhps haplotype (ANRNI-AGEAA) was observed in 56.52% (26/46) cases.
  
  
  CONCLUSIONS
  Overall, high grade of sulphadoxine-pyrimethamine resistance associated genetic polymorphisms were observed among the P. falciparum parasite population in Arunachal Pradesh during the study period.
authors.forename: Jitendra
authors.initials: J
authors.lastname: Sharma
authors.affiliation: Regional Medical Research Centre (ICMR), NE Region, Dibrugarh, Assam, India.
authors.forename: S A
authors.initials: SA
authors.lastname: Khan
authors.forename: Prafulla
authors.initials: P
authors.lastname: Dutta
authors.forename: Jagadish
authors.initials: J
authors.lastname: Mahanta
mesh_terms: D000818:Animals; D000962:Antimalarials / Q000494:pharmacology*; D004094:Dihydropteroate Synthase / Q000235:genetics / Q000378:metabolism*; D004351:Drug Resistance; D057075:Enzyme Assays; D006801:Humans; D016778:Malaria, Falciparum / Q000453:epidemiology / Q000469:parasitology; D010963:Plasmodium falciparum / Q000187:drug effects*; D017354:Point Mutation; D013762:Tetrahydrofolate Dehydrogenase / Q000235:genetics / Q000378:metabolism*
chemical_list: D000962:Antimalarials; D013762:Tetrahydrofolate Dehydrogenase; D004094:Dihydropteroate Synthase