Abstract: Objective   To evaluate the efficacy of albendazole (ABZ) orally administered at different dosages against Trichinella spirails encapsulated larvae in striated muscle in mice.  Methods  A total of 72 BALB/c mice were divided equally into 9 groups. Each mouse was infected orally with 50 T. spiralis encapsulated larvae. At the 29th day after infection, albendazole was each orally administered to the mice of the 8 groups with doses of 50, 100, 150, 200, 250, 300, 350, and 400 mg/（kg·d）, respectively, once a day at fixed time for 6 d. The control group was untreated. Mice were sacrificed at the 7th day post administration. The encapsulated larvae in diaphragmatic muscle, jugomaxillary muscle and gastrocnemius muscle were examined with pellet method. The encapsulated larva that the capsule was complete and the larva inside curled naturally with clear structure was considered survived. The therapeutic effect was estimated on the average quantity of total, survival and dead encapsulated larvae per gram muscle, total worm reduction and survival worm reduction.  Results  The total worm burden and survival worms showed a decreasing trend and the numbers of dead worms increased in diaphragmatic muscle, jugomaxillary muscle and gastrocnemius muscle when the dosage of albendazole were 50-250 mg/（kg·d), but the number of larvae in the muscles remained similar when the dosage of albendazole was greater than 250 mg/kg·d. Compared with the control group, the total and survival worms in the muscles in 200 mg/(kg·d) and the greater dose groups decreased significantly (P＜0.01). In 250 mg/(kg·d) group the total worm reduction in jugomaxillary muscle, diaphragmatic muscle and gastrocnemius muscle were 50.00%, 62.62% and 57.48%, and the survival worm reduction were 79.96%, 83.25% and 80.56%, respectively.  Conclusion  Orally administered to mice for 6 d, albendazole at 250 mg/(kg·d) is a suitable dose against encapsulated larva stage of T. spiralis in muscle.

Key words: Albendazole, Trichinella spiralis, Encapsulated larva, Efficacy, Mouse