Specific and nonspecific responses to Plasmodium falciparum blood-stage parasites and observations on the gametocytemia in schoolchildren living in a malaria-endemic area of Mozambique.
We have observed specific and nonspecific reactivities to the asexual states and gametocytes of Plasmodium falciparum and examined the effect of chloroquine and Fansidar (pyrimethamine/sulfadoxine) on the dynamics of gametocytemia. Schoolchildren peripheral blood films positive for P. falciparum gametocytes were identified in a malaria-endemic area of Mozambique. The children were randomly allocated into two groups to receive chloroquine or pyrimethamine/sulfadoxine, and were followed for 28 days after treatment. In patients harboring drug-sensitive parasites, asexual parasitemias were cleared by day 4, but gametocytes persisted for an additional 17 days. The prevalence of the asexual parasites was 67.6% in the chloroquine-treated group at day 0 and 61.1% at day 28, whereas in the pyrimethamine/sulfadoxine treated group, the initial parasite prevalence of 70.7% was reduced to 2.4% at day 28, suggesting a high prevalence of chloroquine-resistant parasites. On day 0, gametocyte prevalence was 59.5% in the chloroquine-treated group and in 68.3% in the pyrimethamine/sulfadoxine-treated group; these values were reduced to 5.6% and 2.4%, respectively, at day 28. Our results suggest strongly that there is no induction of gametocytogenesis by either course of chemotherapy.
Laboratory of Parasitology, Statens Seruminstitut, Copenhagen, Denmark.
B
B
Hogh
R
R
Thompson
C
C
Hetzel
S L
SL
Fleck
N A
NA
Kruse
I
I
Jones
M
M
Dgedge
J
J
Barreto
R E
RE
Sinden
D000293:Adolescent; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood*; D000953:Antigens, Protozoan / Q000276:immunology; D000962:Antimalarials / Q000494:pharmacology / Q000627:therapeutic use*; D015153:Blotting, Western; D002097:C-Reactive Protein / Q000032:analysis; D002648:Child; D002738:Chloroquine / Q000494:pharmacology / Q000627:therapeutic use*; D003198:Computer Simulation; D004338:Drug Combinations; D004351:Drug Resistance; D004797:Enzyme-Linked Immunosorbent Assay; D005455:Fluorescent Antibody Technique; D006242:Haptoglobins / Q000032:analysis; D006801:Humans; D008163:Luminescent Measurements; D016778:Malaria, Falciparum / Q000188:drug therapy / Q000453:epidemiology / Q000469:parasitology*; D008954:Models, Biological; D009073:Mozambique / Q000453:epidemiology; D018512:Parasitemia / Q000188:drug therapy / Q000453:epidemiology / Q000469:parasitology*; D010963:Plasmodium falciparum / Q000187:drug effects* / Q000276:immunology; D015995:Prevalence; D011739:Pyrimethamine / Q000494:pharmacology / Q000627:therapeutic use*; D011994:Recombinant Proteins / Q000276:immunology; D013413:Sulfadoxine / Q000494:pharmacology / Q000627:therapeutic use*
D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D000962:Antimalarials; D004338:Drug Combinations; D006242:Haptoglobins; D011994:Recombinant Proteins; C001205:fanasil, pyrimethamine drug combination; D013413:Sulfadoxine; D002738:Chloroquine; D002097:C-Reactive Protein; D011739:Pyrimethamine