title: The efficacy of sulfadoxine-pyrimethamine alone and in combination with chloroquine for malaria treatment in rural Eastern Sudan: the interrelation between resistance, age and gametocytogenesis.
abstract: OBJECTIVE
  To compare the efficacy of sulfadoxine-pyremethamine (SP)+chloroquine (CQ) combination treatment against falciparum malaria with SP treatment alone.
  
  
  METHODS
  In-vivo study of 254 patients with uncomplicated Plasmodium falciparum malaria in rural eastern Sudan, where the population is semi-immune.
  
  
  RESULTS
  Sulfadoxine-pyremethamine treatment alone cured 68.3% (41/60) and SP+CQ cured 63.4% (123/194). Early and late treatment failures occurred in both treatment groups. Host age (as a marker for immunity) and parasite gametocytogenesis (as a marker for transmissibility) were significantly associated with SP resistance. Patients who were cured were significantly older (median age 21 years) than patients whose treatment failed (median age 12 years). Gametocyte production was significantly higher in patients with treatment failure (0.72 vs 0.45) and associated with younger age. Gametocyte counts were comparable between both groups until day 7 of follow up; thereafter, they were significantly higher in patients with treatment failure. However, the longevity of gametocytes was comparable in both treatment groups.
  
  
  CONCLUSIONS
  Chloroquine did not improve the parasite response to SP. Age was strongly associated with clearance of SP-resistant parasites. The fast rise of SP resistance may partially be due to selection of SP resistant parasites and expansion of the resistant population through the gametocytogenic effect of SP.
authors.affiliation: Malaria Research Centre, Department of Biochemistry, University of Khartoum, Khartoum, Sudan.
authors.forename: Ishraga E
authors.initials: IE
authors.lastname: A-Elbasit
authors.forename: Mustafa I
authors.initials: MI
authors.lastname: Elbashir
authors.forename: Insaf F
authors.initials: IF
authors.lastname: Khalil
authors.forename: Michael
authors.initials: M
authors.lastname: Alifrangis
authors.forename: Hayder A
authors.initials: HA
authors.lastname: Giha
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000962:Antimalarials / Q000627:therapeutic use*; D002648:Child; D002738:Chloroquine / Q000627:therapeutic use*; D015331:Cohort Studies; D004338:Drug Combinations; D004351:Drug Resistance; D004359:Drug Therapy, Combination; D005260:Female; D005718:Gametogenesis / Q000502:physiology; D006801:Humans; D016778:Malaria, Falciparum / Q000188:drug therapy* / Q000453:epidemiology / Q000635:transmission; D008297:Male; D018512:Parasitemia / Q000453:epidemiology; D011739:Pyrimethamine / Q000627:therapeutic use*; D012423:Rural Health; D013397:Sudan / Q000453:epidemiology; D013413:Sulfadoxine / Q000627:therapeutic use*; D017211:Treatment Failure; D016896:Treatment Outcome
chemical_list: D000962:Antimalarials; D004338:Drug Combinations; C001205:fanasil, pyrimethamine drug combination; D013413:Sulfadoxine; D002738:Chloroquine; D011739:Pyrimethamine