| Summary: | <p>Abstract</p> <p>Background</p> <p>The <it>Plasmodium falciparum </it>dihydrofolate reductase (DHFR) and dihydropteroate synthetase (DHPS) are enzymes of central importance in parasite metabolism. The <it>dhfr </it>and <it>dhps </it>gene mutations are known to be associated with sulphadoxine/pyrimethamine (SP) resistance.</p> <p>Objective</p> <p>To investigate the effects of <it>dhfr/dhps </it>mutations on parasite characteristics other than SP resistance.</p> <p>Method</p> <p>Parasite infections obtained from 153 Sudanese patients with uncomplicated falciparum malaria treated with SP or SP + chloroquine, were successfully genotyped at nine codons in the <it>dhfr/dhps </it>genes by PCR-ELISA.</p> <p>Results & conclusion</p> <p>Mutations were detected in <it>dhfr </it>at N51I, S108N and C59R, and in at <it>dhps </it>at A/S436F, A437G, K540E and A581G, the maximum number of mutations per infection were five. Based on number of mutant codons per infection (multiplicity of mutation, MOM), the infections were organized into six grades: wild-types (grade 0; frequency, 0.03) and infections with MOM grades of 1 to 5, with the following cumulative frequency; 0.97, 0.931, 0.866, 0.719, 0.121, respectively. There was no significant association between the MOM and SP response. Importantly, immunity, using age as a surrogate marker, contributed significantly to the clearance of parasites with multiple <it>dhfr/dhps </it>mutations. However, these mutations have a survival advantage as they were associated with increased gametocytogenesis. The above implications of <it>dhfr/dhps </it>mutations were associated with MOM 2 to 5, regardless of the gene/codon locus.</p>
|
|---|