目的　探讨日本血吸虫对吡喹酮敏感性是否改变 ,为调整防治策略和修订日本血吸虫病治疗方案提供依据。方法　在江苏省南京、镇江市各选择 1个沿江血吸虫病低度流行村 ,对村中人群作粪便检查 ,进行病原学诊断 ,阳性者为观察对象 ,做个案调查。对观察对象分别按 6 0 mg/kg或 4 0mg/kg吡喹酮抗虫治疗。治疗 6周后粪检复查 ,阳性者进行第 2次治疗。第 2次治疗 6周后再粪检 ,体内仍有活卵排出者 ,结合以往病史和治疗情况 ,可被认为体内存在对吡喹酮不敏感虫株。结果　4 3例观察对象中 ,有吡喹酮抗虫治疗史 1次者 16人 ,2次以上者 2 7人 ;中度感染 10人 (EPG2 16～312 ) ,轻度感染 33人 (EPG2 4～ 96 ) ,第 1次治疗使用吡喹酮 6 0 mg/kg30人 ,4 0 m g/kg13人 ,复查均未查见毛蚴或虫卵。结论　目前 ,在血吸虫病低度流行区 ,日本血吸虫对吡喹酮仍保持着较高的敏感性。 Objective To investigate whether the susceptibility of Schistosoma japonicum to praziquantel changed or not, so as to provide evidences for adjusting control strategy and revising the treatment plan of schistosomiasis japonica. Methods One low-prevalence village of schistosomiasis along the river was selected in Nanjing, Jiangsu Province and Zhenjiang City, and stool examination was conducted for the crowd in the village. Pathogen diagnosis was performed. The positive persons were observed, and the case was investigated. The subjects were treated by 60 mg / kg or 40 mg / kg praziquantel respectively. After 6 weeks of treatment, the fecal examination was performed and the positive patients were treated for the second time. After the second treatment for 6 weeks and then in the fecal examination, the body still has ovulation excretion, combined with past medical history and treatment, can be considered in vivo praziquantel insecticidal strains. Results Among the 43 cases, there were 16 patients who were treated with praziquantel for 1 time in the first instance and 27 persons who were more than 2 times; 10 were moderately infected (EPG2 16 ~ 312) and 33 were mildly infected (EPG2 4 ~ 96), the first treatment with praziquantel 60 mg / kg30, 40 mg / kg13, did not see the review of miracidia or eggs. Conclusion Currently, Schistosoma japonicum still maintains high sensitivity to praziquantel in the endemic areas of schistosomiasis.