title: Direct evidence that asparagine at position 108 of the Plasmodium falciparum dihydrofolate reductase is involved in resistance to antifolate drugs in Tanzania.
abstract: A nested polymerase chain reaction was used to amplify a fragment of the gene for dihydrofolate reductase of Plasmodium falciparum containing codon 108, where a point mutation, causing a serine to asparagine change, occurs in pyrimethamine resistant parasites. The presence of the mutation was detected by restriction enzyme digestion. Parasites in blood samples collected from asymptomatic children before, and 3 weeks after, treatment with pyrimethamine-sulfadoxine or chlorproguanil-dapsone were analysed. Parasites in the samples taken at 3 weeks carried only the asparagine mutant.
authors.affiliation: London School of Hygiene and Tropical Medicine, UK.
authors.forename: J
authors.initials: J
authors.lastname: Curtis
authors.forename: M T
authors.initials: MT
authors.lastname: Duraisingh
authors.forename: J K
authors.initials: JK
authors.lastname: Trigg
authors.forename: H
authors.initials: H
authors.lastname: Mbwana
authors.forename: D C
authors.initials: DC
authors.lastname: Warhurst
authors.forename: C F
authors.initials: CF
authors.lastname: Curtis
mesh_terms: D000818:Animals; D002648:Child; D002675:Child, Preschool; D004351:Drug Resistance / Q000235:genetics; D005493:Folic Acid Antagonists / Q000627:therapeutic use*; D006801:Humans; D007223:Infant; D010963:Plasmodium falciparum / Q000235:genetics*; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D013762:Tetrahydrofolate Dehydrogenase / Q000235:genetics*
chemical_list: D005493:Folic Acid Antagonists; D013762:Tetrahydrofolate Dehydrogenase