洞庭湖区黄鳝体内鳗鲡独孤吸虫的流行病学调查

2002年7~8月份,对洞庭湖区6个采样点鳗鲡独孤吸虫(AzygiaAnguillae)对黄鳝(Monopterusalbus)的感染情况进行了调查。结果显示,6个采样点的鳗鲡独孤吸虫对黄鳝的感染存在较大差异。感染率以华容点的最高(51·7%),津市点次之(46·7%),其余4个采样点的感染率都较低(20%以下);感染强度也一样,华容点的最高,为4·7,津市点次之,为3·1,不同采样点的感染强度之间不存在显著性差异(P>0·05)。2002年6月至2003年5月对常德采样点周年取样调查,发现在6、7、9月和翌年1、4、5月黄鳝感染有鳗鲡独孤吸虫,感染率在1·6%~18·4%间波动(以7月份最高),感染强度在1·0~17·0间变化(以4月份最高),其余月份无感染,全年总感染率为3·5%,平均感染强度为5·41。全部阳性宿主的体长频率呈正态分布,以30~35cm体长段的阳性宿主最多,占37·7%。不同地域环境、不同月份之间的感染差异性,与水域环境的稳定程度和作为中间宿主的食饵动物(多种小型鱼类)数量分布的均一性,以及鳗鲡独孤吸虫的生活史及黄鳝的习性等因素相关。

Epidemiological Investigation of Azygia anguillae in the Host Monopterus albus from Dongting Lake Region

In July and August,2002,the infection difference of the rice-field eel Monopterus albus by Azygia anguillae from six localities of Dongting Lake region was reported.The prevalence was high in Huarong and Jinshi,which was 51.7% and 46.7% respectively;and it was all less than 20% in another four localities.The greatest intensity4.7(1～33)] occured in Huarong,and Jinshi came the second3.1(1～11)].Intensity difference among six localities were not significant(P>0.05).In Changde,the overall prevalence and mean intensity from June 2002 to May 2003 were 3.5% and 5.41(1～79)respectively.There was infection in June,July,September and January,April,May of the next year,the prevalence was 1.6%~18.4%(highest in July),and mean intensity was 1.0~17.0(greatest in April);there were no infection in other months.The frequency distribution of the positive host was the normal distribution,the positive rate of host among 30～35cm body length was the highest(37.7%).The infection difference in different localities and different months was related to the stability of water environment and regular distribution of the middle host(small-sized fishes)and life cycle of Azygia anguillae and habits of the rice-field eel etc.