title: Molecular epidemiology of malaria in Cameroon. XI. Geographic distribution of Plasmodium falciparum isolates with dihydrofolate reductase gene mutations in southern and central Cameroon.
abstract: The DNA sequence of the dihydrofolate reductase (dhfr) gene, a molecular marker for pyrimethamine resistance, was determined for 178 field isolates of Plasmodium falciparum collected along the east-west axis in southern Cameroon. The proportion of isolates having the wild-type dhfr allele varied from 48.1% in the east (city of Bertoua) to 11.3-15.7% in central provinces (Yaounde and Eseka) and 0% in the littoral region (port city of Douala). Isolates with a single Asn-108 mutation or double mutations (Ile-51 or Arg-59 and Asn-108) constituted approximately 10% of the samples. Isolates with triple mutations (Ile-51, Arg-59, and Asn-108) were present in an equal proportion (48.1%) as the wild-type isolates in the east (Bertoua), while triple mutations predominated in Yaounde (62.3%), Eseka (62.7%), and Douala (78.9%). The distribution of triple dhfr mutations along the east-west axis in southern Cameroon suggests the presence of a decreasing gradient from the west coastal region to the central region and then to the east towards the interior of the country.
authors.affiliation: Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC) and Unité de Recherche Paludologie Afro-tropicale, Institut de Recherche pour le Développement (IRD), Yaounde, Cameroon.
authors.forename: Leonardo K
authors.initials: LK
authors.lastname: Basco
authors.forename: Mathieu
authors.initials: M
authors.lastname: Ndounga
authors.forename: Mathurin
authors.initials: M
authors.lastname: Tejiokem
authors.forename: Vincent Foumane
authors.initials: VF
authors.lastname: Ngane
authors.forename: Jean-Christian
authors.initials: JC
authors.lastname: Youmba
authors.forename: Pascal
authors.initials: P
authors.lastname: Ringwald
authors.forename: Georges
authors.initials: G
authors.lastname: Soula
mesh_terms: D000483:Alleles; D000818:Animals; D001483:Base Sequence; D002163:Cameroon / Q000453:epidemiology; D002675:Child, Preschool; D017931:DNA Primers; D005787:Gene Frequency; D006801:Humans; D007223:Infant; D016778:Malaria, Falciparum / Q000453:epidemiology* / Q000235:genetics; D017720:Molecular Epidemiology; D009154:Mutation; D010963:Plasmodium falciparum / Q000201:enzymology / Q000235:genetics*; D016133:Polymerase Chain Reaction; D013762:Tetrahydrofolate Dehydrogenase / Q000235:genetics*
chemical_list: D017931:DNA Primers; D013762:Tetrahydrofolate Dehydrogenase