ABSTRACT
[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.