对虾一种新病毒病的细胞超微病变及其诊断

The Ultrastructural Cytopathological Changes of a New Virus Disease in Shrimps and Their Diagnostics

应用电镜超薄切片技术，研究ＬＮＢＶ引起的对虾细胞超微病理变化的结果表明，ＬＮＢＶ的靶细胞依次为淋巴样细胞、表皮细胞、肌样细胞和组织细胞．病虾主要症状是甲壳上有呈放射状或菊花状白斑．在病理切片上可见巨大细胞核，依病程发展，有的核无结构化，有的有各种异物积聚，有的遍布囊泡，有的密集着大量ＬＮＢＶ粒子，并造成核固缩或者核膜极度扩张、破裂而崩解．这些病理过程、病变特点和具有特殊构型的ＬＮＢＶ粒子的存在，可作为该病毒病的特征性诊断指标．膜性系统广泛髓样变性和肌原原纤维排列紊乱和肌节断裂，在其他杆状病毒病不多见，可作为诊断该病毒病的重要辅助性指标．而细菌继发感染对评估预后和指导捕捞是有价值的．文中讨论了ＬＮＢＶ作用机制．

with the ultrathin technique of EM., the ultramicroscopic pathological changes of shrimp cells from naturally and experimentally infected shrimps by a baculovirus,lymphold cell nuclear baculovirus(LNBV) are lymphoid cells,epithelial cells, muscle-like cells and histocytes. The symptoms of the diseased shrimps are the appearance of obvious white spots which are in the form of radium and chrysanthemum on the inside surface of the carapace. In noumal sections, large nuclei, destructuralized nuclei in certain developing stage of disease, and muclei thick with LNBV virion,which made nuclear pycnosis or nuclear envelop extreme expansion,rapture and collapse,can sometimes be seen. These pathological process,pathologlcal change characteristic and the existence of LNBV with specific configurations can be treated as special diagnosis index. The popularly marrow-like denaturation of membranous system and disorder of primary myofibril or myomere break have not been seen in other virosis,so those can act as the important auxiliary diagnosis index for this virosis. Bacterium Infection following virus is a signal to guide harvest and evaluate prognosis. We also discusse the mechanism of LNBV infection and believe that LNBV weakened disease-resistant ability of shrimps by destroy the immune function of lymphoid cells,and the digestive and assimilationg function by destroy muscle cells which promoting gut wriggle. We have not detected any LNBV virion and pathological changes in the shrimps of control experiments.