Reddacliff L A, Whittington R J
New South Wales Agriculture, Elizabeth Macarthur Agricultural Institute, Camden, Australia.
J Comp Pathol. 1996 Aug;115(2):103-15. doi: 10.1016/s0021-9975(96)80033-8.
The gross and histopathological lesions of epizootic haematopoietic necrosis virus (EHNV) infection in rainbow trout (Oncorhynchus mykiss Walbaum) and redfin perch (Perca fluviatilis L) were examined during epidemiological studies on an endemically infected trout farm and in experimentally infected fish of the same two species maintained in the laboratory. Intercurrent infections were common in rainbow trout in field outbreaks, producing a variety of lesions and clinical signs, but the following changes were considered due to infection with EHNV in rainbow trout, based on experimental infections. Clinically, moribund fish were dark in colour, inappetent and sometimes ataxic. Gross lesions included abdominal distension, swelling of the spleen and kidney, and, rarely, pale foci in the liver. Microscopical lesions included focal to extensive, acute renal haematopoietic necrosis; multiple tiny foci of acute hepatocellular necrosis; focal to extensive, acute splenic necrosis; mild branchial hyperplasia with occasional focal necrosis; congestion, oedema and necrosis in the wall of the swim bladder; and focal acute necrotizing myocarditis, necrotic cells and debris being prominent within the cardiac lumen (and within blood vessels throughout the body generally). Round to oval basophilic intracytoplasmic inclusions were commonly present in hepatocytes surrounding necrotic foci and were sometimes seen in cells in the interstitium of the kidney, or in the spleen. Less common lesions included focal necrosis of the pancreas, thyroid, pseudobranch, thymus and gastrointestinal crypt epithelium. Intercurrent infections were not observed in redfin perch; gross lesions included multiple pale foci in the liver, haemorrhages at the bases of the fins, swelling of the spleen and kidney, and focal haemorrhages in the gills. Microscopical lesions in haematopoietic kidney, liver, spleen and heart were similar to those in rainbow trout, but the livers had larger focal to locally extensive areas of necrosis. Thrombosis, haemorrhage and fibrinous exudate were common in the gills, and focal to extensive pancreatic necrosis was frequently found. Focal necrosis of the lamina propria of the intestine was also seen. Immunoperoxidase staining in both species revealed EHNV antigen associated with areas of necrosis and in inclusions.
在一个地方性感染鳟鱼养殖场的流行病学研究期间，以及在实验室饲养的相同两个物种的实验感染鱼中，对虹鳟（Oncorhynchus mykiss Walbaum）和红鳍鲈（Perca fluviatilis L）感染流行性造血坏死病毒（EHNV）后的大体和组织病理学病变进行了检查。在野外暴发中，并发感染在虹鳟中很常见，会产生多种病变和临床症状，但基于实验感染，以下变化被认为是虹鳟感染EHNV所致。临床上，濒死鱼体色变黑，食欲不振，有时共济失调。大体病变包括腹部膨胀、脾脏和肾脏肿大，肝脏偶尔出现苍白病灶。显微镜下病变包括局灶性至广泛性急性肾造血坏死；多个微小的急性肝细胞坏死灶；局灶性至广泛性急性脾坏死；轻度鳃增生伴偶尔的局灶性坏死；鳔壁充血、水肿和坏死；以及局灶性急性坏死性心肌炎，坏死细胞和碎片在心脏腔（以及全身血管内）突出。圆形至椭圆形嗜碱性胞质内包涵体通常存在于坏死灶周围的肝细胞中，有时也可见于肾间质或脾脏中的细胞。较少见的病变包括胰腺、甲状腺、伪鳃、胸腺和胃肠隐窝上皮的局灶性坏死。红鳍鲈未观察到并发感染；大体病变包括肝脏多个苍白病灶、鳍基部出血、脾脏和肾脏肿大以及鳃部局灶性出血。造血肾、肝脏、脾脏和心脏的显微镜下病变与虹鳟相似，但肝脏有更大的局灶性至局部广泛性坏死区域。鳃中血栓形成、出血和纤维蛋白渗出常见，且经常发现局灶性至广泛性胰腺坏死。还可见肠道固有层局灶性坏死。两种物种的免疫过氧化物酶染色均显示EHNV抗原与坏死区域和包涵体相关。
