Killing effect of ivermectin on migratory-stage schistosomula of Schistosoma japonicum

Abstract

Objective To screen an effective drug which can kill migratory-stage schistosomula of Schistosoma japonicum (S. j) from macrocyclic drugs treating other pathogenic infections. Methods Firstly, 3 doses of clarithromycin (ClM), azithromycin (AzM) and ivermectin (IVM) were used to kill the migratory-stage schistosomula in vitro. The behavior changes and difference in methylene blue staining were used as markers to distinguish the death or life of the worms. The mortality of each group was employed to evaluate the killing effects of different drug groups. IVM at the dose of highly killing effectiveness was used to treat the mice in 1 to 4 d after S.j infection in order to observe the therapeutic effect. Results IVM at a concentration of 20 μg/mL showed 100% killing effect against early-stage schistosomula in vitro, which was significantly higher than that of praziquantel (PZQ) and artesunate (ARS) (P < 0.05). When IVM was used to treat the mice at the dose of 0.4 mg/kg×2, the killing rate of S.j was 53.37% in 1~2 d (P < 0.01) and 39.98% in 3~4 d (P < 0.05) after infection, with statistical difference when compared with the control group. No synergistic or additive effect was observed when IVM was combined with PZQ or ARS. Conclusion Among macrocyclic drugs, IVM exerts good killing effect on migratory-stage schistosomula of S.j in vivo and in vitro.

Keywords

• schistosoma japonicum
• skin-stage schistosomula
• migratory-stage
• schistosomula
• ivermectin
• molluscicidal efficacy