title: High frequency of Plasmodium falciparum chloroquine resistance marker (pfcrt T76 mutation) in Yemen: an urgent need to re-examine malaria drug policy.
abstract: BACKGROUND
  Malaria remains a significant health problem in Yemen with Plasmodium falciparum being the predominant species which is responsible for 90% of the malaria cases. Despite serious concerns regarding increasing drug resistance, chloroquine is still used for the prevention and treatment of malaria in Yemen. This study was carried out to determine the prevalence of choloroquine resistance (CQR) of P. falciparum isolated from Yemen based on the pfcrt T76 mutation.
  
  
  METHODS
  A cross-sectional study was carried out among 511 participants from four governorates in Yemen. Blood samples were screened using microscopic and species-specific nested PCR based on the 18S rRNA gene to detect and identify Plasmodium species. Blood samples positive for P. falciparum were used for detecting the pfcrt T76 mutation using nested-PCR.
  
  
  RESULTS
  The prevalence of pfcrt T76 mutation was 81.5% (66 of 81 isolates). Coastal areas/foothills had higher prevalence of pfcrt T76 mutation compared to highland areas (90.5% vs 71.8%) (p = 0.031). The pfcrt T76 mutation had a significant association with parasitaemia (p = 0.045). Univariate analysis shows a significant association of pfcrt T76 mutation with people aged > 10 years (OR = 9, 95% CI = 2.3 - 36.2, p = 0.001), low household income (OR = 5, 95% CI = 1.3 - 19.5, p = 0.027), no insecticide spray (OR = 3.7, 95% CI = 1.16 - 11.86, p = 0.025) and not sleeping under insecticide treated nets (ITNs) (OR = 4.8, 95% CI = 1.38 - 16.78, p = 0.01). Logistic regression model confirmed age > 10 years and low household income as predictors of pfcrt T76 mutation in Yemen P. falciparum isolates.
  
  
  CONCLUSIONS
  The high prevalence of pfcrt T76 mutation in Yemen could be a predictive marker for the prevalence of P. falciparum CQR. This finding shows the necessity for an in-vivo therapeutic efficacy test for CQ. P. falciparum CQR should be addressed in the national strategy to control malaria.
authors: Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia. halkasemi@yahoo.com
authors: Abdulsalam M
authors: AM
authors: Al-Mekhlafi
authors: Mohammed A K
authors: MA
authors: Mahdy
authors: Hesham M
authors: HM
authors: Al-Mekhlafi
authors: Ahmed A
authors: AA
authors: Azazy
authors: Mun Yik
authors: MY
authors: Fong
references: Acta Trop. 2006 Jan;97(1):19-25
references: 16171768
references: Acta Trop. 2003 Jul;87(2):287-93
references: 12826304
references: East Mediterr Health J. 2007 Jan-Feb;13(1):35-40
references: 17546903
references: Trop Biomed. 2010 Dec;27(3):551-8
references: 21399597
references: Am J Trop Med Hyg. 2007 May;76(5):844-8
references: 17488902
references: EMBO J. 2005 Jul 6;24(13):2294-305
references: 15944738
references: Parasitol Int. 2009 Sep;58(3):201-9
references: 19393762
references: Acta Trop. 2006 May;98(2):137-44
references: 16620743
references: Malar J. 2009 Jul 30;8:178
references: 19642978
references: Am J Trop Med Hyg. 2004 Mar;70(3):256-9
references: 15031513
references: Malar J. 2006 Aug 30;5:76
references: 16939658
references: Parasit Vectors. 2011 Mar 16;4:37
references: 21410946
references: Parasit Vectors. 2011 Mar 31;4:46
references: 21453465
references: Am J Trop Med Hyg. 2007 Apr;76(4):619-25
references: 17426159
references: Trans R Soc Trop Med Hyg. 2009 Jan;103(1):72-8
references: 18950826
references: Infect Genet Evol. 2003 Nov;3(4):287-92
references: 14636690
references: Parasitol Res. 2007 Feb;100(3):487-93
references: 17096149
references: Acta Trop. 2005 Jan;93(1):97-106
references: 15589802
references: Ann Saudi Med. 2007 Nov-Dec;27(6):432-6
references: 18059124
references: Am J Trop Med Hyg. 2003 Aug;69(2):184-7
references: 13677373
references: Lancet. 2001 Sep 15;358(9285):890-1
references: 11567708
references: Trop Med Int Health. 2004 Aug;9(8):857-61
references: 15303989
references: Nature. 2002 Feb 7;415(6872):680-5
references: 11832956
references: Parasit Vectors. 2010 Nov 19;3:110
references: 21092097
references: J Infect Dis. 2004 Aug 15;190(4):853-5
references: 15272415
references: J Egypt Soc Parasitol. 2003 Dec;33(3):829-39
references: 14708856
references: Trends Parasitol. 2002 May;18(5):224-30
references: 11983604
references: Malar J. 2010 May 17;9:131
references: 20478015
references: Acta Trop. 2006 Feb;97(2):181-7
references: 16336938
references: N Engl J Med. 2001 Jan 25;344(4):257-63
references: 11172152
references: East Mediterr Health J. 2005 Jul;11(4):606-17
references: 16700375
references: Acta Trop. 2011 Jul;119(1):11-3
references: 21300016
references: Parasitology. 2003 May;126(Pt 5):401-5
references: 12793643
references: East Mediterr Health J. 2003 Sep-Nov;9(5-6):1048-53
references: 16450536
references: Am J Pathol. 2007 Jun;170(6):1817-9
references: 17525250
references: Ann Trop Med Parasitol. 2004 Dec;98(8):879-82
references: 15667720
references: Chemotherapy. 2006;52(4):166-70
references: 16720983
references: BMJ. 2006 Oct 21;333(7573):827
references: 17053235