Plasmodium vinckei petteri: identification of the stages sensitive to arteether.

Antimalarial activity of arteether, a derivative of artemisinin (qinghaosu) against blood-induced infections of the highly synchronous Plasmodium vinckei petteri rodent species of malaria was evaluated in Swiss mice. A single subcurative dose of arteether of 2.2 mg/kg body weight was injected subcutaneously to mice, either during the prepatent period or during the patent infection, when different stages of the parasitic cycle were present in the blood. It was shown that rings and young trophozoites were the most susceptible stages to arteether. The drug had no effect on merozoites and little effect on mid-term trophozoites which is the stage most sensitive to chloroquine. The alcoholic solution (10% alcohol in sterile water) had an immediate effect while the oily solution (miglyol 840) was active between 3 and 21 hr after injection.