洞庭湖区黄鳝体内新棘衣棘头虫的流行病学调查

Epidemiological investigation of Pallisentis (Neosentis) celatus in the host Monopterus albus from Dongting Lake basin

2002年6月至2003年5月,对洞庭湖周边6个县(市)不同水域环境黄鳝体内新棘衣棘头虫的流行病学进行调查研究.结果显示,2002年7、8月的感染率以岳阳点最高(93.6%),常德点次之(53.1%),华容点第3(36.2%),其余3个采样点的感染率都较低(20%以下);平均感染强度(个/尾)以岳阳点最高(13.7),湘阴点次之(6.3),岳阳点显著大于津市(1.3)、沅江(2.5)、华容(4.1)和常德点(5.9),华容点、常德点显著大于津市点.通过周年取样调查,发现常德点相同体长段(25～40cm)黄鳝在不同月份的感染有比较明显的季节变化,感染率在7月(51.1%)、10月(34.8%)、12月(31.0%)和翌年4月(61.8%)出现4个峰值,而在2月和3月感染率最低(6.0%以下);平均感染强度则在7月(6.2)、10月(7.4)和翌年1月(5.7)、5月(7.8)出现4个峰值,12月最低(1.9).表明不同采样点、不同月份之间感染的差异性,与所处水域环境的稳定程度、中间宿主——劳氏中剑水蚤的丰富度及其季节变化,以及终宿主——黄鳝的生活习性等因素相关.全部阳性宿主的频率呈正态分布,以体长30～35cm的阳性宿主最多(占29.6%),其次为体长25～30cm的宿主(占26.5%).

From June 2002 to May 2003, the epidemiological investigation of Pallisentis （Neosentis） celatus in the rice-field eel Monopterus albus from six localities of Dongting Lake basin was reported. In June or August 2002, the highest prevalence was in locality Yueyang （93.6%）, followed by Changde, （53.1%）, and followed once again by Huarong locality （36.2%）, but it was all less than 20% in the other three localities. The mean intensity was bigger （6.3, 5.9） in Xiangyin and Changde localities, while one was biggest （13.7） in Yueyang locality in June or August 2002. Xiangyin locality （6.3） not included, mean intensity between five localities were significant （P〈0.05）. In Changde locality, the overall prevalence and mean intensity from June 2002 to May 2003 were 29.3% and 6.72 respectively, and distinct seasonality of the prevalence and mean intensity of the host body length between 25cm to 40 cm was observed. Even though it was all less than 6.0% in February and March, the prevalence arose four peaks in July （51.1%）, October （34.8%） and December （31.0%）, April of the following year and mean intensity was the lowest in December （1.9） and reached four peaks in July （6.2）, October （7.4）, the following January （5.7） and May （7.8）. These are related to the stable degree of water environments, the richness and seasonality of the intermediate host （Mesocyclops leuckarti） and feeding habits of the rice-field eel etc. Frequency distribution of the positive host was the normal distribution, the positive rate of host among 30--35 cm body length by the acanthocephalan was highest （29.6%）, and 25~30 cm next （26.5%）.