鱼类淋巴囊肿病毒靶器官的组织病理研究

Histopathological Studies on Target Organs of Lymphocystis Disease Virus of Fish

探讨病毒传播途径，运用组织病理学技术，对患淋巴囊肿病毒病的牙鲆和鲈鱼的组织进行显微观察，并对病毒感染的靶器官进行了研究。结果表明，在牙鲆体表皮下结缔组织中，当大量成纤维细胞膨大、变圆，大小为10～18μm时，细胞膜外未出现囊壁，少数细胞的细胞质中观察到嗜碱性物质；18～20μm的膨大细胞在细胞膜外出现囊壁，细胞质内出现嗜碱性物质；〉20μm的细胞具有了淋巴囊肿细胞的典型特征。另外，在牙鲆鳃、肠上皮下结缔组织和粘膜下层中，脾、头肾边缘组织和表面系膜、肝表面系膜，以及鲈鱼的鳃等部位均观察到淋巴囊肿细胞，并在牙鲆和鲈鱼脾内观察到膨大细胞。因此，淋巴囊肿病毒的靶器官主要是鱼体表皮下结缔组织，其次是鳃、体腔膜、肠、脾和头肾。鱼体表皮下结缔组织是淋巴囊肿病毒病的检测、检疫和早期诊断的最佳样品。

Structural features of the tissues of Japanese flounder Paralichthys olivaceus and common sea bass Lateolabraxjapomicus infected by lymphocystis disease virus （LCDV） were studied using histopathological methods, and the target organs of LCDV were determined. The results indicated that numerous fibroblasts turned round and hypertrophied in the connective tissue beneath the epidermis of fish body surface, the cytoplasm became incompact and vacuolated. The hypertrophied cells with the size of 10- 18μm showed no capsule outside the cell membrane, and only a few basophilic substances were found in the cytoplasm of some cells; The hypertrophied cells with the size of 18-20 μm had capsules outside the cell membrane and basophilic inclusion bodies in the cytoplasm; The cells more than 20 μm possessed the typical structural features of lymphocystis cells of fish. Furthermore, lymphocystis cells were observed in the gill, connective tissue beneath the epithelial cells and the submueosa of intestine, the spleen, the peripheral tissue and the surface of head kidney, and the adjacent mesenteries of liver in P. olivaceus, as well as the gill of L. japonicus ; Also, obvious hypertrophied cells were seen in the spleen of P. olivaceus and L. japonicus. Therefore the main target organ of LCDV is the connective tissue beneath the epidermis of body surface of fish, which is the optimum specimen for the detection and the quarantine of LCDV, and the early diagnosis of lymphoeystis disease; In addition, the target organs include the gill, visceral mesentery, spleen, intestine, and head kidney.