Effects of albendazole,artesunate,praziquantel and miltefosine,on Opisthorchis viverrini cercariae and mature metacercariae

Objective:To explore larvicidal effects of anthelmintic drugs on Opisthorchis viverrini（O.viverrini） for alternative approach to interrupting its cycle for developing a field-based control program.Methods:The larvicidal activities of albendazole（A1）,artesunate（Ar）,praziquantel（Pzq） and miltefosine（Mf） on O.viverrini cercariae and mature metacercariae were investigated.Lethal concentrations(LC;and LC;) of these drugs were determined.Mature metacercariae previously exposed to various concentrations of the drugs were administered to hamsters.Worms were harvested 30 d post infection and worm recovery rates calculated.Al,Ar,Pzq and Mf produced morphological degeneration and induced shedding tails of cercariae after 24 h exposure.Results:The LC;and LC;of Al,Ar,Pzq and Mf on cercariae were 0.720 and 1.139,0.350 and 0.861,0.017 and 0.693,and 0.530 and 1.134 ppm,respectively.LC;and LC;of Ar on mature metacercariae were 303.643 and 446.237 ppm and of Mf were 289.711 and 631.781 ppm,respectively but no lethal effect in Pzq-and Al-treated groups（up to 1 ppt）.No worms were found in hamsters administered Pzq-treated metacercariae.The adult worms from Al-treated metacercariae were significantly bigger in size compared to the control group（P<0.05）.Fecundity and body width were greater in adults from Mf-treated metacercariae compared to the control group（P<0.05）.Conclusions:The larvicidal effects of these drugs were high efficacy to O.viverrini cercariae but lesser efficacy to metacercariae.It should be further studied with the eventual aim of developing a field-based control program.