虾夷扇贝大规模死亡的流行病学研究及可能致病因子的探讨

Identification of Possible Pathogenic Factors of Massive Mortality and Its Epidemiological Investigation of Cultured Scallop(Patinopecten yessoensis)

为对辽宁省长海县虾夷扇贝大规模死亡的可能性致病因子进行研究,于2010年3～10月在辽宁省长海县虾夷扇贝养殖海区进行虾夷扇贝大规模死亡的流行病学调查,结合电镜检测、病原粗提和人工感染试验等实验方法,发现患病虾夷扇贝器官的结缔组织细胞和间质细胞中存在一种球形病毒,可引起相应的病理学变化。但人工感染实验结果显示,感染实验组濒死扇贝未表现出与自然海区发病扇贝相同的临床症状,不同温度条件下,感染组与空白对照组的扇贝死亡率差异不大(P>0.05),该病毒粒子可能不是导致虾夷扇贝大规模死亡的直接病原。室内养殖实验结果显示:17℃养殖实验组死亡率明显高于其它3个温度梯度养殖实验组(P<0.01)。结合流行病学调查数据表明,高温可能是导致虾夷扇贝大规模死亡的主要原因之一,而17℃很可能就是虾夷扇贝开始大规模死亡的起始温度。

Pathogenic factors of massive mortality of scallop（Patinopecten yessoensis） cultured in Changhai,Liaoning Province,were identified in 2010 with methods including electromicroscopic examination of ultrathin sections,pathogenic isolation and artificial infection.Spherical virus-like particles were found in moribund scallop,and relevant pathologic changes were observed.However,virus was not the cause of abnormal mortality as was showed in artificial infection;the symptom appeared after artificial infection was not similar to that of diseased scallop under natural condition and the mortality of infective groups and the controls was similar each other（P0.05）.The mortality at 17 ℃ was higher than that at other lower temperatures（P0.01）.Therefore,high temperatures equal or higher than 17 ℃ were clearly related with the massive morality of this scallop.