为观察多子小瓜虫(Ichthyophthirius multifiliis)感染草鱼免疫相关器官的病理学变化,人工进行草鱼小瓜虫感染,酯酶染色方法检测血液中T、B淋巴细胞的百分比,然后采用常规染色(H.E)和透射电镜方法观察各组草鱼鳃、肝和脾脏的结构变化。结果显示:感染组T淋巴细胞百分率明显高于B淋巴细胞百分率;光学显微镜下:感染组草鱼鳃丝上皮网状结构消失,细胞变性、坏死,有小瓜虫虫体;肝脏的肝板结构紊乱,细胞变性、坏死,窦间隙充满红细胞;脾脏红髓和白髓结构紊乱,淋巴细胞变性、坏死;透射电镜下,感染组草鱼鳃丝超微结构遭受严重破坏,细胞内可见残存细胞结构碎片和小瓜虫虫体;肝板完整结构断裂,细胞核溶解或消失;脾脏淋巴细胞数量减少,核周间隙消失。说明:感染小瓜虫的草鱼免疫相关器官损伤严重,各器官细胞以变性、坏死为主要特征,酯酶染色结果揭示草鱼感染小瓜虫初期以T淋巴细胞免疫为主。 In order to observe the pathological changes of immune-related organs in grass carp infected with Ichthyophthirius multifiliis, the percentage of T and B lymphocytes in blood was detected by esterase staining, ) And transmission electron microscopy were used to observe the changes of gill, liver and spleen in grass carp. The results showed that the percentage of T lymphocytes in infected group was significantly higher than that of B lymphocytes. Under optical microscope, the reticular structure of gill filaments in grass carp disappeared, the cells became degenerated and necrotic, , Cell degeneration, necrosis and sinus gap were filled with erythrocytes; spleen red marrow and white pulp were disorganized and lymphocytes degenerated and necrotic. Under the transmission electron microscope, the ultrastructure of gill filaments in grass carp severely damaged and the remaining cell structure fragments Small melon worm body; liver plate intact structure rupture, nucleus dissolve or disappear; spleen lymphocyte number decreases, the perinuclear space disappears. The results showed that the immune-related organs of grass carp infected with small melon were severely damaged, and the degeneration and necrosis of each organ were the main characteristics. The result of esterase staining showed that the immune response of small melon was mainly T lymphocyte.