湖沼地区不同地理株日本血吸虫尾蚴对吡喹酮的敏感性

Sensitivity to praziquantel in cercariae of different geographical isolates of Schistosoma japonicum from marshland and lake regions of China

目的测定并比较湖沼型流行区不同地理株日本血吸虫尾蚴对吡喹酮的敏感性差异。方法在我国湖沼型血吸虫病流行区湖南、湖北、江西、安徽和江苏省疫区现场采集感染性钉螺,于实验室内收集新鲜逸出的日本血吸虫尾蚴并分别暴露于10-5、5×10-6、10-6、5×10-7和10-7 mol/L吡喹酮溶液中,20、40、60、80和100min后在解剖镜下观察各地理株的断尾情况,计算断尾率及40min时的吡喹酮半数致死浓度(50%lethal concentration,LC50)。结果经相同浓度吡喹酮溶液作用一定时间后,各地理株日本血吸虫尾蚴断尾率差异无统计学意义(P>0.05)。吡喹酮对湖南、湖北、江西、安徽和江苏湖沼区日本血吸虫尾蚴作用40min的LC50分别为6.32×10-7、1.78×10-7、1.61×10-7、1.66×10-7和1.62×10-7 mol/L,差异无统计学意义(P>0.05)。结论中国大陆不同地理株日本血吸虫尾蚴对吡喹酮的敏感性无显著差异。因此,通过测定并比较不同地理株日本血吸虫尾蚴对吡喹酮的敏感性,可为建立吡喹酮抗药性检测/监测技术提供参考依据。

Objective To determine and compare the sensitivity to praziquantel of cercariae of different geographical isolates of Schistosoma japonicumfrom marshland and lake regions of China. Methods Oncomelania snails infected with S.japonicum were collected from endemic foci in marshland and lake regions of China,including Hunan,Hubei,Jiangxi,Anhui,and Jiangsu provinces.Freshly released cercariae were collected and exposed to praziquantel at concentrations of 10^-5,5×10^-6,10^-6,5×10^-7,and 10^-7 mol/L for 20,40,60,80,and 100 min.Tail shedding of cercariae was observed under a microscope,and the rate of tail shedding and 50%lethal concentration（LC50value）of praziquantel at 40 min were calculated. Results Following exposure to praziquantel at concentrations of 10^-5,5×10^-6,10-6,5×10^-7,and 10^-7 mol/L for 20,40,60,80,and 100 min,the rate of tail shedding of cercariae of the Hunan,Hubei,Jiangxi,Anhui,or Jiangsu isolates of S.japonicumranged from 0to 100%;however,there were no significant differences in the rate of tail shedding of cercariae of different geographical isolates of S.japonicum（P〉0.05）after treatment with praziquantel at the same concentration for the same time.The LC50 of praziquantel at 40 min for cercariae of the Hunan,Hubei,Jiangxi,Anhui,and Jiangsu isolates of S.japonicum was 6.32×10^-7,1.78×10^-7,1.61×10^-7,1.66×10^-7,and1.62×10^-7 mol/L,respectively.No significant differences in LC50 values were noted（P〉0.05）. Conclusion There were no significant differences in praziquantel sensitivity among cercariae of different geographical isolates of S.japonicumfrom marshland and lake regions of China.Evaluation of sensitivity to praziquantel among cercariae of different geographical isolates of S.japonicum will provide evidence to establish techniques for detection and monitoring of praziquantel resistance.