海南省乐东县恶性疟原虫对氯喹抗性的变化

目的：监测海南省停用氯喹后抗氯喹恶性疟原虫对氯喹抗性的消长。方法：选择恶性疟原虫对氯喹有高度抗性且恶性疟发病率较高的海南省乐东县为观察点，采用ＷＨＯ标准体外微量法和体内四周法，间隔一定时间检测一次。结果：停用氯喹１８年，体外法，抗性率由１９８１年的９７．９％下降至１９９７年的２６．７％（Ｐ＜０．００１），完全抑制裂殖体形成的平均药浓度由１０．４６±７．１４ｐｍｏｌ／μｌ血降至１．６３±１．４７ｐｍｏｌ／μｌ血（Ｐ＜０．００１）；体内法，抗性率由１９８１年的８４．２％降为１９９７年的１８．４％（Ｐ＜０．００１），ＲⅢ占抗性病例的比例由５３．１％降为１４．３％。结论：海南省停用氯喹后恶性疟原虫对氯喹逐渐恢复了敏感性

Changes in chloroquine resistance of Plasmodium falciparum in Hainan province]

AIM: To observe the variation in resistance of Plasmodium falciparum after the cessation of chloroquine medication. METHODS: WHO standard in vitro microtest and in vivo test were used. RESULTS: In vitro test showed that the rate of chloroquine-resistant P. falciparum dropped from 97.9% in 1981 to 26.7% in 1997 (P < 0.001). The mean concentration of chloroquine for complete inhibition of schizont formation declined from 10.46 +/- 7.14 pmol/ul blood in 1981 to 1.63 +/- 1.47 pmol/microliter blood in 1997(P < 0.001). In vivo test showed that the rate of chloroquine-resistant P. falciparum decreased from 84.2% in 1981 to 18.4% in 1997(P < 0.001). The proportion of R III cases to the total resistant cases dropped from 53.1% in 1981 to 14.3% in 1997. CONCLUSION: A tendency of progressive decline of resistance of the parasite was revealed after the cessation of chloroquine medication.