title: Survey of chloroquine-resistant mutations in the Plasmodium falciparum pfcrt and pfmdr-1 genes in Hadhramout, Yemen.
abstract: Malaria is still a major public health problem in Yemen. More than 95% of the malaria cases are due to Plasmodium ‎falciparum‎. Recently in Yemen, the antimalarial treatment policy was changed from chloroquine (CQ) to artemisinin combination therapy (ACTs). However, CQ is still available and prescribed in the Yemeni market. The persistence of CQ resistance will be prolonged if the shift to ACT and the simultaneous withdrawal of CQ are not rigorously implemented. The aim of the current survey is to detect chloroquine-resistant mutations in P. falciparum chloroquine-resistance transporter (pfcrt) and P. falciparum multi-drug resistance-1 (pfmdr1) genes. These data will be important for future monitoring and assessment of antimalarial drug policy in Yemen. Blood specimens were collected from 735 individuals from different districts of the Hadhramout province, Yemen by house-to-house visit. Mutation-specific nested polymerase chain reaction (PCR) and restriction fragment length polymorphism (PCR-RFLP) methods were used to investigate the mutations in the pfmdr1(codons 86 and 1246) and pfcrt (codons 76, 271, 326, 356 and 371) genes. The overall prevalence of pfcrt mutations at codons 76, 271, 326 and 371 were 50.4%, 58.7%, 54.3% and 44.9%, respectively. All isolates had wild-type pfcrt 356 allele. The majority of pfmdr1 86 alleles (83.3%) and all pfmdr1 1246 alleles were wild type. There was no association between pfcrt mutations and symptomatology, gender and age groups. In conclusion, point mutations in codons 76, 271, 326 and 371 of pfcrt of P. falciparum are high suggesting a sustained high CQ resistance even after 4 years of shifting to ACTs. These findings warrant complete withdrawal of CQ use from the Yemeni market for P. falciparum and careful usage of CQ for treating Plasmodium vivax.
authors.affiliation: Department of Parasitology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia.
authors.forename: Omar A A
authors.initials: OA
authors.lastname: Bamaga
authors.affiliation: Department of Parasitology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia; Tropical Disease Research Center, University of Science and Technology, Sana'a, Yemen; Department of Parasitology, Faculty of Medicine, Sana'a University, Yemen. Electronic address: alsharaby9@yahoo.com.
authors.forename: Mohammed A K
authors.initials: MA
authors.lastname: Mahdy
authors.affiliation: Department of Parasitology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia. Electronic address: limailian@um.edu.my.
authors.forename: Yvonne A L
authors.initials: YA
authors.lastname: Lim
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000483:Alleles; D000962:Antimalarials; D002648:Child; D002675:Child, Preschool; D002738:Chloroquine; D004351:Drug Resistance / Q000235:genetics*; D005260:Female; D005838:Genotype; D006801:Humans; D007223:Infant; D016778:Malaria, Falciparum / Q000453:epidemiology / Q000469:parasitology*; D008297:Male; D026901:Membrane Transport Proteins / Q000235:genetics*; D008875:Middle Aged; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics*; D009154:Mutation; D010963:Plasmodium falciparum / Q000235:genetics*; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D015800:Protozoan Proteins / Q000235:genetics*; D011795:Surveys and Questionnaires; D015006:Yemen / Q000453:epidemiology; D055815:Young Adult
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
keywords: Drug resistance; Hadhramout-Yemen; Malaria; Molecular marker