title: Mutations of pvdhfr and pvdhps genes in vivax endemic-malaria areas in Kota Marudu and Kalabakan, Sabah.
abstract: BACKGROUND
  Malaria cases persist in some remote areas in Sabah and Sarawak despite the ongoing and largely successful malaria control programme conducted by the Vector Borne Disease Control Programme, Ministry Of Health, Malaysia. Point mutations in the genes that encode the two enzymes involved in the folate biosynthesis pathway, dihydrofolate reductase (DHFR) and dihydropteroate synthase (DHPS) enzymes confer resistance to pyrimethamine and sulfadoxine respectively, in both Plasmodium falciparum and P. vivax. The aim of the current study was to determine the mutation on both pvdhfr at codon 13, 33, 57, 58, 61, 117, and 173 and pvdhps genes at codon 383 and 553, which are potentially associated with resistance to pyrimethamine and sulfadoxine in P. vivax samples in Sabah.
  
  
  METHODS
  Every individual was screened for presence of malaria infection using a commercial rapid dipstick assay, ParaMax-3™ (Zephyr Biomedical, India). Individuals tested positive for P. vivax had blood collected and parasite DNA extracted. The pvdhfr and pvdhps genes were amplified by nested-PCR. Restriction fragment length polymorphism (RFLP) was carried out for detection of specific mutations in pvdhfr at codons 13Leu, 33Leu, 57Ile/Leu, 58Arg, 61Met, 117Asn/Thr, and 173Leu and pvdhps at codons 383Gly and 553Gly. The PCR-RFLP products were analysed using the Agilent 2100 Bioanalyzer (Agilent Technology, AS).
  
  
  RESULTS
  A total of 619 and 2119 individuals from Kalabakan and Kota Marudu, respectively participated in the study. In Kalabakan and Kota Marudu, 9.37 and 2.45 % were tested positive for malaria and the positivity for P. vivax infection was 4.2 and 0.52 %, respectively. No mutation was observed at codon 13, 33 and 173 on pvdhfr and at codon 553 on pvdhps gene on samples from Kalabakan and Kota Marudu. One-hundred per cent mutations on pvdhfr were at 57Leu and 117Thr. Mutation at 58Arg and 61Met was observed to be higher in Kota Marudu 72.73 %. Mutation at 383Gly on pvdhps was highest in Kalabakan with 80.77 %. There are four distinct haplotypes of pvdhfr/pvdhps combination.
  
  
  CONCLUSIONS
  The presence of triple and quintuple mutation combination suggest that the P. vivax isolates exhibit a high degree of resistant to sulfadoxine, pyrimethamine and sulfadoxine-pyrimethamine combination therapy.
authors: Herbal Medicine Research Centre, Institute for Medical Research, Ministry of Health, Jalan Pahang, 50588, Kuala Lumpur, Malaysia. umie_1902@yahoo.com.my.
authors: Umi Rubiah
authors: UR
authors: Sastu
authors: Herbal Medicine Research Centre, Institute for Medical Research, Ministry of Health, Jalan Pahang, 50588, Kuala Lumpur, Malaysia. noorrain@imr.gov.my.
authors: Noor Rain
authors: NR
authors: Abdullah
authors: Herbal Medicine Research Centre, Institute for Medical Research, Ministry of Health, Jalan Pahang, 50588, Kuala Lumpur, Malaysia. azrina@imr.gov.my.
authors: Nor Azrina
authors: NA
authors: Norahmad
authors: Herbal Medicine Research Centre, Institute for Medical Research, Ministry of Health, Jalan Pahang, 50588, Kuala Lumpur, Malaysia. mnfarhan@imr.gov.my.
authors: Muhammad Nor Farhan
authors: MN
authors: Saat
authors: Herbal Medicine Research Centre, Institute for Medical Research, Ministry of Health, Jalan Pahang, 50588, Kuala Lumpur, Malaysia. prem_khs@hotmail.com.
authors: Prem Kumar
authors: PK
authors: Muniandy
authors: Sabah State Health Department, Level 3, Rumah Persekutuan, Jalan Mat Salleh, 88590, Kota Kinabalu, Sabah, Malaysia. drjenarun@gmail.com.
authors: Jenarun
authors: J
authors: Jelip
authors: District Health Office Kota Marudu, PO Box 421, 89108, Kota Marudu, Sabah, Malaysia. tmoizin@yahoo.com.
authors: Moizin
authors: M
authors: Tikuson
authors: District Health Office Kota Marudu, PO Box 421, 89108, Kota Marudu, Sabah, Malaysia. hazimnsy@yahoo.com.
authors: Norsalleh
authors: N
authors: Yusof
authors: Faculty of Science and Technology, School of Bioscience and Biotechnology, Universiti Kebangsaan Malaysia, 43600, Bangi, Malaysia. hasidahmohdsidek@yahoo.com.
authors: Hasidah Mohd
authors: HM
authors: Sidek
mesh_terms: D004094:Dihydropteroate Synthase / Q000235:genetics*; D006239:Haplotypes / Q000235:genetics; D006801:Humans; D016780:Malaria, Vivax / Q000453:epidemiology / Q000469:parasitology*; D008296:Malaysia / Q000453:epidemiology; D009154:Mutation; D010966:Plasmodium vivax / Q000235:genetics / Q000472:pathogenicity; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D015800:Protozoan Proteins / Q000235:genetics*; D013762:Tetrahydrofolate Dehydrogenase / Q000235:genetics*
chemical_list: D015800:Protozoan Proteins; D013762:Tetrahydrofolate Dehydrogenase; D004094:Dihydropteroate Synthase