Gametocyte clearance in uncomplicated and severe Plasmodium falciparum malaria after artesunate-mefloquine treatment in Thailand.
Artemisinin-based combination therapy (ACT) is currently promoted as a strategy for treating both uncomplicated and severe falciparum malaria, targeting asexual blood-stage Plasmodium falciparum parasites. However, the effect of ACT on sexual-stage parasites remains controversial. To determine the clearance of sexual-stage P. falciparum parasites from 342 uncomplicated, and 217 severe, adult malaria cases, we reviewed and followed peripheral blood sexual-stage parasites for 4 wk after starting ACT. All patients presented with both asexual and sexual stage parasites on admission, and were treated with artesunate-mefloquine as the standard regimen. The results showed that all patients were asymptomatic and negative for asexual forms before discharge from hospital. The percentages of uncomplicated malaria patients positive for gametocytes on days 3, 7, 14, 21, and 28 were 41.5, 13.1, 3.8, 2.0, and 2.0%, while the percentages of gametocyte positive severe malaria patients on days 3, 7, 14, 21, and 28 were 33.6, 8.2, 2.7, 0.9, and 0.9%, respectively. Although all patients were negative for asexual parasites by day 7 after completion of the artesunate-mefloquine course, gametocytemia persisted in some patients. Thus, a gametocytocidal drug, e.g., primaquine, may be useful in combination with an artesunate-mefloquine regimen to clear gametocytes, so blocking transmission more effectively than artesunate alone, in malaria transmission areas.
Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. tmntp@mahidol.ac.th
Noppadon
N
Tangpukdee
Srivicha
S
Krudsood
Siripan
S
Srivilairit
Nanthaporn
N
Phophak
Putza
P
Chonsawat
Wimon
W
Yanpanich
Shigeyuki
S
Kano
Polrat
P
Wilairatana
D000293:Adolescent; D000328:Adult; D000818:Animals; D000962:Antimalarials / Q000494:pharmacology* / Q000627:therapeutic use; D037621:Artemisinins / Q000494:pharmacology* / Q000627:therapeutic use; D000077332:Artesunate; D004341:Drug Evaluation; D004359:Drug Therapy, Combination; D005260:Female; D005500:Follow-Up Studies; D005854:Germ Cells / Q000187:drug effects* / Q000254:growth & development; D006801:Humans; D016778:Malaria, Falciparum / Q000188:drug therapy* / Q000469:parasitology; D008297:Male; D015767:Mefloquine / Q000494:pharmacology* / Q000627:therapeutic use; D010963:Plasmodium falciparum / Q000187:drug effects* / Q000254:growth & development; D012720:Severity of Illness Index; D013785:Thailand; D016896:Treatment Outcome
D000962:Antimalarials; D037621:Artemisinins; D000077332:Artesunate; D015767:Mefloquine