[Artesunate in interrupting the transmission of Plasmodium falciparum].
OBJECTIVE
To observe the effect of artesunate (ATS) on the infectivity of Plasmodium falciparum gametocytes (PFG).


METHODS
31 volunteers with falciparum malaria and gametocytaemia were randomly divided into 3 groups: artesunate (ATS) group (15 cases), quinine (QN) group (10 cases) and placebo group (6 cases). Each case in ATS group received 6-day course of oral artesunate (200 mg at 0, 6 and 24 hours then 100 mg daily for 4 days). Cases in QN group each received 21-dose course of quinine sulfate (500 mg/time) over seven days. Cases in placebo group took 2 tablets of vitamin B composites, three times per day for seven days. Peripheral PFG were counted daily in all cases until the clearance of PFG. Mosquitoes (Anopheles dirus) were fed with venous blood of patients on the 1st, 7th, 14th, 21st and 28th day, respectively.


RESULTS
All cases in placebo group were PFG positive at the whole course by blood smear examinations. The PFG relative density in ATS group were (12.5+/-3.3)%, (1.2+/-0.4)%, (0.3+/-0.1)% on 7th, 14th, 21st day respectively, and the mean PFG clearance time was (22.0+/-1.4) d. The PFG relative density in QN group were (173.9+/-47.0)%, (112.5+/-45.4)%, (32.5+/-17.8)% at 7th, 14th, 21st day respectively, and the mean clearance time of PFG was (32.5+/-2.1) d (t=4.731, P<0.01). PFG remained positive on the 28th day in placebo group. The infectivity test to mosquitoes showed on 14th day the positive rate in ATS group, QN group and placebo group were 0, 35.0% and 48.7% respectively. In ATS group, the sporozoite rate of anopheline mosquitoes were 14.8% and 0 at 7th, 14th day, while in QN group, 142.0%, 98.6% and 20.3% at 7th, 14th, 21st day respectively. In placebo group, the infection rate of sporozoites remained stable.


CONCLUSIONS
Oral administration of artesunate with a total dosage of 1000 mg in 6 days inhibits the infectivity of PFG.
Chen
Pei-Quan
PQ
Tropical Medicine Institute, Guangzhou University of Chinese Medicine, Guangzhou 510405, China. pqchen@21cn.com
Xu
Ying
Y
Chen
Dong
D
He
Kun-Rong
KR
Ou
Feng-Zhen
FZ
Fu
Chong-Wei
CW
Fu
Lin-Chun
LC
Li
Guo-Qiao
GQ
D000293:Adolescent; D000328:Adult; D000818:Animals; D000852:Anopheles / Q000469:parasitology; D000962:Antimalarials / Q000627:therapeutic use*; D037621:Artemisinins / Q000627:therapeutic use*; D000077332:Artesunate; D002648:Child; D005260:Female; D006801:Humans; D016778:Malaria, Falciparum / Q000188:drug therapy* / Q000635:transmission*; D008297:Male; D008875:Middle Aged; D010963:Plasmodium falciparum / Q000187:drug effects; D055815:Young Adult
D000962:Antimalarials; D037621:Artemisinins; D000077332:Artesunate