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Objective To investigate the therapeutic effect of the method of Fast Elimination of Malaria by Source Eradication (FEMSE) in Moheli island of Comoros. Methods Based on the FEMSE project, parasite positive cases were given a standard treatment course of ARTEQUICK (artemisinin plus piperaquine) plus primaquine: two tablets for adults at 0 hour and two tablets at 24 hours, a total of 4 tablets during one treatment course. One time of Mass Drug Administration (MDA) was for the children with parasite carrier rate less than 10%. Two times of MDA was for the children with parasite carrier rate more than 10%, and the interval between the two MDA was 42 days. Coverage rate for MDA and population carrier rate were observed. Results The number of people taking the first MDA of Artequick-Primaquine was 32,519 (the whole population registered at the same time being 37,243, 367 infants under 6 months old not involved), and the coverage rate for MDA was 88.2%. The population involved in the second MDA was 35,370 (the whole population registered at the same time being 37,112, 335 infants under 6 months old not involved), and the coverage rate for MDA was 96. 2%. Parasite carrier rate was 22.95% (281/ 1,224) before MDA, 1.41% (28/1, 987) two months after MDA and 0. 33% (8/2,458) four months after MDA, with a decrease of 98.56% . Conclusion The decrease of parasite carrier rate from 22. 95% to 0. 33% before and after MDA indicates that MDA of Artequick-Primaquine based on FEMSE can decrease the parasite carrier rate in a short time, without any obvious side effects. Further decrease of parasite carrier rate and incidence will be achieved if the measures for clearing malaria are fully implementated during the consolidation phase.
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[Objective] To examine the sensitivity of P. falciparum to the components of dihydroartemisinin (DHA) and piperaquine (PQ) in Dihydroartemisinin Compounds. [Methods] WHO (World Health Organization) standard micro test and in-vitro test were used. [Results] Survey in the year of 2001 for 61 cases and in 2004 for 28 cases showed that the DHA-resistant rate of P. falciparum in all cases was zero with inhibitory concentration of 50% (IC50) being 6.84 nmol/L and 5.67 nmol/L, and the mean concentration for complete inhibition of schizont formation was 35 nmol/L and 39 nmol/L, respectively. Survey in the year of 2001 for 75 cases and in 2004 for 29 cases showed that PQ-resistant rate of P. falciparum was 22.67% and 17.24% with IC50 being 274 nmol/L and 317 nmol/L, and the mean concentration for complete inhibition of schizont formation was 1 220 nmol/L and 1 269 nmol/L, respectively. [Conclusion] No DHA -resistance exists and PQ-resistance decreases for the treatment of P. falciparum in Dongfang city of Hainan province.
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Objective To study the effects of dihydroartemisinin and quinine on plasmodium falciparum gametocytes at early stage. Methods Eleven patients with falciparum malaria who had plasmodium falciparum gametocytes at early stage(PFGe) in bone marrow but no matured plasmodium falciparum gametocytes(PFGm) in bone marrow and peripheral blood were allocated to two groups.Group A(n=6) were administered orally with dihydroartemisinin at a total dosage of 480mg for 7 days and Group B(n=5) with quinine sulfate at a total dosage of 10?500 mg for 7 days.The number of gametocytes in bone marrow and peripheral blood was examined at regular time. Results PFGe in bone marrow disappeared in Group A on 10 th day after the first administration while existed in all the cases of Group B on 10 th day and still in 2 cases on 14 th day.The clearance time for peripheral PFGe was 4.8?0.9 days in Group A and 22.0?5.8 days in Group B. Conclusion Dihydroartemisinin can clear PFGe but quinine shows no this action.
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A study was carried out in south of Vietnam 15 Patients with Plasmodium falciparum gametocytes and asexual parasites were distributed into groups A, B and C. Artesunate was given orally at a total dose of 600 mg for 5 days in group A, 200 mg for 2 days in group B and intravenously at a total dose of 360 mg for 5 days in group C respectively. Gametocytes count was done before medication and daily after medication. Meanwhile, Anopheles dirus as a vector was employed to study the infectivity of gametocyte, The result showed that the mean gametocyte clearance time in three groups were respectively 15.4?5.0, 20.6?4.8 and 20.3?4.0 days. The mosquitoes were not infected from the blood in 2, 5 and 5 of 5 patients respectively on days 7, 14 and 21 in group A; 1 and 5 of 5 patients on day 14 and 21 in group B; 2 of 5 patients and 3 of 3 patients on days 14 and 21 in group C. It indicates that artesunate has remarkable effect on Plasmodium falciparum gametocytemia and its infectivity to mosquitoes.
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Objective To identify the genotype of merozoite surface protein 1 (MSP1) of Plasmodium falciparum isolates from Hainan Province. Methods Nested PCR was applied to amplify the MSP1 of Blocks 2 and 3 Plasmodium falciparum isolates from Hainan Province. Two allelic family representitive gene fragments were sequenced.Results From 36 out of 39 blood samples from Plasmodium falciparum patients, 44 gene fragments of blocks 2 and 3 of the MSP1 were amplified, of which the MAD20 type allele was dominant(75%). followed by K1 type allele. No RO33 type allele was found. The mixed infection rate of the two different allelic type was 19 4%. Sequence analysis showed that the sequences of MAD20 and K1 type isolates from Hainan Province were highly homologous to that of the MAD20 and K1 allelic prototypes.Conclusion Two principal allelic types of MSP1 gene, MAD20 and K1 type, exist in malaria endemic areas in Hainan Province, the MAD20 type being the dominant.