中文摘要：

研究采用4种不同的人工感染方式,对模式鱼种金鱼实施镰刀菌（Fusarium spp.）FF08人工感染,以期探讨镰刀菌在不同感染方式下对鱼体的致病强度,同时通过石蜡切片和HE染色进一步研究了其对鱼体组织病理性损伤机制。结果表明：腹腔、肌肉和创伤感染均对金鱼有很强的致死性,15d内死亡率分别达到100%、93%和100%,鱼体均出现与自然发病相同的发病症状。病理分析表明镰刀菌FF08感染可引起鱼体肌肉组织、肝、肾、肠道均出现较严重的损坏。主要表现为肌纤维细胞变性、坏死、溶解,大量炎细胞浸润,并有菌丝侵入肌肉组织;肝细胞水肿、充血、出血、血管发生血栓,并且镰刀菌分生孢子侵入组织,有强烈的细胞炎性反应;肾脏充血、出血、部分组织坏死崩解;肠道堵塞、肠系膜脱落等病理症状。研究将为鱼类镰刀菌病的侵染机制及防治奠定理论基础。

英文摘要：

Infections caused by Fusarium have increased in recent years in freshwater fish. However, few reports to data have described the pathogenicity and histopathology concerning Fusarium-infection in fish. We have isolated a Fusarium species from Carasslus auratus and have identified it as Fusarium oxysporum. In this paper, four kinds of different infection methods had been used to artificially infect the model fish species-goldfish with Fusarium oxysporum strain FF08, the intention of which was to explore the Fusarium pathogenicity in fish under different infection modes. At the same time, paraffin section and HE staining were also applied to study the pathological mechanism in the artificial infected fish. The results showed that intraperitoneal injection, intramuscular injection and wound infection could cause high mortality in the goldfish and the mortality were up to 100%, 93% and 100% in 15d respectively. However, there were no fish die in bath infection group. These results suggested Fusarium infection in fish maybe associated with some primary pathogenic factor, for example wound or bad living environment. Fusarium could cause high pathogenicity only when they had the change to invade the epidermis. Infected fish have shown the common clinical symptoms as naturally. HE staining revealed that Fusarium FF08 is harmful to fish muscle tissue, liver, kidney and intestinal canal. Muscle fiber cells showed degeneration and necrosis, with a large number of inflammatory cell infiltration, and there also found invasive hyphae. Liver cell was edema. Congestion and vascular thrombosis were occurred. Conidiophores could intrude into blood vessel. In addition, hepatic tissue had a strong inflammatory response. Kidney tissue was hyperemia and part of it was necrosis collapse. The mesentery was desquamated. We speculated if broad hypha penetrated the mucous membrane and invade ground substance, blood vessel may be the important target organ. The focal necrosis would extend around the blood vessel. When their hypha had made in