The differing impact of chloroquine and pyrimethamine/sulfadoxine upon the infectivity of malaria species to the mosquito vector

Research output: Contribution to journalJournal articleResearchpeer-review

  • Høgh, Birthe
  • A Gamage-Mendis
  • G A Butcher
  • R Thompson
  • K Begtrup
  • C Mendis
  • S M Enosse
  • M Dgedge
  • J Barreto
  • W Eling
  • R E Sinden

Using serum or infected blood from Danish volunteers and Plasmodium falciparum-infected Mozambican patients, respectively, the impact of curative doses of chloroquine and pyrimethamine/sulfadoxine upon infectivity of P. falciparum to Anopheles arabiensis and An. gambiae or of P. berghei to An. stephensi was studied. Both treatments cleared circulating P. falciparum gametocytes within 28 days. Before this clearance, chloroquine enhanced infectivity to An. arabiensis, whereas pyrimethamine/sulfadoxine decreased infectivity. Patients harboring chloroquine-resistant parasites as opposed to -sensitive ones were 4.4 times more likely to have gametocytes following treatment. In contrast, pyrimethamine/sulfadoxine-resistant parasites were 1.9 times less likely to produce gametocytes. In laboratory infections using replicated P. berghei or P. falciparum preparations, serum from chloroquine-treated, uninfected, nonimmune volunteers enhanced gametocyte infectivity with increasing efficiency for 21 days following treatment, whereas pyrimethamine/sulfadoxine significantly suppressed infectivity. The observed enhancement in infectivity induced by the use of chloroquine combined with increased gametocytemias in chloroquine-resistant strains may in part explain the rapid spread of chloroquine resistance in endemic populations.

Original languageEnglish
JournalAmerican Journal of Tropical Medicine and Hygiene
Volume58
Issue number2
Pages (from-to)176-82
Number of pages7
ISSN0002-9637
Publication statusPublished - Feb 1998

    Research areas

  • Animals, Anopheles/parasitology, Antimalarials/pharmacokinetics, Carrier State/drug therapy, Chloroquine/pharmacokinetics, Drug Combinations, Drug Resistance, Female, Humans, Insect Vectors/parasitology, Malaria/drug therapy, Malaria, Falciparum/drug therapy, Mice, Mozambique/epidemiology, Plasmodium berghei/drug effects, Plasmodium falciparum/drug effects, Prevalence, Pyrimethamine/pharmacokinetics, Risk Factors, Sulfadoxine/pharmacokinetics

ID: 202981889