title: Molecular epidemiology of drug-resistant Plasmodium falciparum in Benguela province, Angola.
abstract: BACKGROUND
  The malaria situation has been worsening in Angola, partly due to armed conflict until the recent past and drug-resistant Plasmodium falciparum. Malaria transmission is heterogeneous within the country, and data on drug-resistant malaria in different parts of the country are incomplete. The aim of the present study was to evaluate resistance to 4-aminoquinolines and antifolate drugs in P. falciparum isolates collected in Benguela province, central Angola, using molecular markers.
  
  
  METHODS
  Fingerprick capillary blood was collected from asymptomatic children aged less than 15 years old during a household survey in and around Balombo town in 2010-2011. Samples were screened for P. falciparum by nested PCR. Molecular markers (P. falciparum dihydrofolate reductase [pfdhfr], P. falciparum dihydropteroate synthase [pfdhps], P. falciparum chloroquine resistance transporter [pfcrt], and P. falciparum multidrug-resistance gene 1 [pfmdr1]) were sequenced to determine the key codons associated with drug resistance.
  
  
  RESULTS
  A total of 60 blood samples were positive for P. falciparum. Most isolates with successful PCR amplification had mutant pfdhfr alleles, with either double mutant AICNI (69%) or triple mutant AIRNI (21%) haplotypes. A16V, S108T, and I164L substitutions were not found. Many of the isolates were carriers of either SGKAA (60%) or AGKAA (27%) pfdhps haplotype. K540E substitution was absent. There were only two pfcrt haplotypes: wild-type CVMNK (11%) and mutant CVIET (89%). Wild-type pfmdr1 NYSND haplotype was found in 19% of the isolates, whereas single mutant pfmdr1 YYSND and NFSND haplotypes occurred in 48% and 11%, respectively. Double mutant pfmdr1 haplotypes (YFSND and YYSNY) occurred rarely.
  
  
  CONCLUSIONS
  The results suggest that the high prevalence of mutant pfcrt CVIET haplotype is in agreement with low clinical efficacy of chloroquine observed in earlier studies and that the double pfdhfr mutant AICNI and single pfdhps mutant SGKAA are currently the predominant haplotypes associated with antifolate resistance in Benguela province. The hallmark of clinical resistance observed in East Africa, i.e. triple pfdhfr mutant haplotype (AIRNI) and double pfdhps mutant haplotype (SGEAA), was absent. These molecular findings need to be further evaluated in parallel with clinical studies, in particular with the efficacy of intermittent preventive treatment using sulphadoxine-pyrimethamine in pregnant women and artesunate-amodiaquine for uncomplicated malaria.
authors.affiliation: Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), B. P. 288, Yaoundé, Cameroon. vfoumane@yahoo.fr.
authors.forename: Vincent
authors.initials: V
authors.lastname: Foumane Ngane
authors.affiliation: Laboratoire de Pharmacodynamie Biochimique, Unité de Formation et de Recherche (UFR) Biosciences, Université Félix Houphouët-Boigny (Cocody), 22 BP 582, Abidjan, 22, Côte d'Ivoire. djamanj@yahoo.fr.|Département de Biochimie, Institut Pasteur de Côte d'Ivoire, 01 BP 490, Abidjan, 01, Côte d'Ivoire. djamanj@yahoo.fr.
authors.forename: Joseph
authors.initials: J
authors.lastname: Allico Djaman
authors.affiliation: Unité Mixte de Recherche 216 Mère et Enfant Face aux Infections Tropicales, Institut de Recherche pour le Développement (IRD), Unité de Formation et de Recherche (UFR) de Pharmacie, Université Paris Descartes, 4 avenue de l'Observatoire, 75270, Paris, France. cecile.culeux@etu.parisdescartes.fr.
authors.forename: Cécile
authors.initials: C
authors.lastname: Culeux
authors.affiliation: Unité Mixte de Recherche 216 Mère et Enfant Face aux Infections Tropicales, Institut de Recherche pour le Développement (IRD), Unité de Formation et de Recherche (UFR) de Pharmacie, Université Paris Descartes, 4 avenue de l'Observatoire, 75270, Paris, France. piettenathalie.pn@gmail.com.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Piette
authors.affiliation: Malaria Control Programme, Société nationale de métallurgie (Sonamet), rua 1 de Dezembro, caixa postal 479, Lobito, Provincia de Benguela, Angola. pcarnevale2001@yahoo.fr.
authors.forename: Pierre
authors.initials: P
authors.lastname: Carnevale
authors.affiliation: Malaria Control Programme, Société nationale de métallurgie (Sonamet), rua 1 de Dezembro, caixa postal 479, Lobito, Provincia de Benguela, Angola. patrick.besnard@subsea7.com.
authors.forename: Patrick
authors.initials: P
authors.lastname: Besnard
authors.affiliation: Plano National Contra Malaria, Ministry of Health, Luanda, Angola. filomenofortes@gmail.com.
authors.forename: Filomeno
authors.initials: F
authors.lastname: Fortes
authors.affiliation: Unité de Recherche 198-Institut de Recherche pour le Développement (IRD), Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes (URMITE), Faculté de Médecine La Timone, Aix-Marseille Université, 27 boulevard Jean Moulin, 13385, Marseille, France. lkbasco@yahoo.fr.
authors.forename: Leonardo K
authors.initials: LK
authors.lastname: Basco
authors.affiliation: Unité Mixte de Recherche 216 Mère et Enfant Face aux Infections Tropicales, Institut de Recherche pour le Développement (IRD), Unité de Formation et de Recherche (UFR) de Pharmacie, Université Paris Descartes, 4 avenue de l'Observatoire, 75270, Paris, France. rachida.tahar@ird.fr.
authors.forename: Rachida
authors.initials: R
authors.lastname: Tahar
mesh_terms: D000293:Adolescent; D000810:Angola / Q000453:epidemiology; D000962:Antimalarials / Q000494:pharmacology*; D002648:Child; D002675:Child, Preschool; D004351:Drug Resistance; D005819:Genetic Markers; D006239:Haplotypes; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D016778:Malaria, Falciparum / Q000453:epidemiology*; D010963:Plasmodium falciparum / Q000187:drug effects* / Q000235:genetics*; D016133:Polymerase Chain Reaction; D015800:Protozoan Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D000962:Antimalarials; D005819:Genetic Markers; D015800:Protozoan Proteins