Preventive effect of artemether in rabbits infected with Schistosoma japonicum cercariae

AIM: To study the effect of artemether (Art) for prevention of schistosomal infection. METHODS: Rabbits with single infection or reinfection with Schistosoma japonicum cercariae were treated intramuscularly (im) or intragastrically (ig) with Art 5 -20 mg · kg -1 on d 7 - 15 after the first infection, followed by various regimens. RESULTS: When rabbits were injected in Art 7.5 mg · kg -1 (ie, one half of the effective dose given ig on d 7) followed by once every week for twice, the ♀ worm reduction rate was only 41 %. In infected rabbits treated ig with Art 10 - 20 mg · kg -1 given in the same administration schedule, the ♀ worm reduction rates were >91 %. When Art 15 mg · kg -1 was given to rabbits on d 7 - 14 and the following dose of the drug was given at intervals of 7 - 14 d, the ♀ worm reduction rates were > 94%. In rabbits reinfected with cercariae, the ♀ reduction rate of Art given ig once a week for 3 times since d 8 after the first infection was 96 % which was similar to that given once a week twice since d 14 after the first infection. CONCLUSION: Art should be given ig on d 7 - 15 after infection, followed by repeated dosing once every 7 - 15 d for a total of 3 doses. Art given ig daily for 2 consecutive days or given at 1-wk intervals since 7 - 15 d after infection also showed preventive effect.