急性病毒性鲫鳃出血病的病理变化

病毒性鲫(Carassius auratus)鳃出血病的突发流行可导致鱼高致死率,使中国部分养鱼场近些年受到重创。为了充分认识这种鱼病的发生发展过程,我们结合PCR、光学显微镜和透射电镜,对病鱼头肾等组织的病变及病毒分布情况进行了分析。注射自然发病鱼的组织滤液(病毒悬液),能使正常鲫感染,且出现与自然发病鲫相同的症状及高致死率;病原有典型疱疹病毒的形态特征(故称为鲫疱疹病毒,Ca HV)。经PCR扩增对已知鲤科疱疹病毒主要衣壳蛋白(MCP)基因进行检测,可确定Ca HV存在于被感染鱼的肝、脾、肾和头肾组织中。对组织病理变化及不同时序进行比较,结果表明Ca HV感染会引起鲫这些组织不同程度病变,而鳃和头肾的病理变化有显著时序相关性。在头肾细胞中还观察到大量Ca HV颗粒,预示鲫头肾是Ca HV侵染和复制的主要靶器官。

Pathological changes of acute viral hemorrhages in the gills of crucian carp

Acute outbreaks of gill hemorrhages of crucian carp (Carassius auratus) can cause high mortality rates, and the viral disease in China has had a devastating effect on some fish farms in recent years. To better understand the pro-gression of the viral disease, we combined polymerase chain reaction (PCR) technology and light microscopy with electron microscopy to observe the pathological changes and virus distribution in the gill and head-kidney of diseased fish. Normal crucian carps were infected by injection with tissue filtrate (viral suspension) from naturally infected fish, which caused similar symptoms to those observed in naturally infected fish, and high mortality. The pathogen has the morphological characteristics of a typical herpesvirus (referred to asCarassius auratusherpesvirus, CaHV). CaHV can be determined in infected fish tissues, liver, spleen, kidney and head-kidney, using a PCR assay for the major capsid protein (MCP) gene of the known cyprinid herpesvirus. The pathological changes in different tissues, such as the gill and head-kidney, were compared at different times after infection with CaHV. The results showed that CaHV caused varying degrees of pathological change among the various tissues. The pathological changes in the gills and head-kidney increased with time after CaHV infection. There were a large number of virus particles in the head-kidney cells, suggesting that the head-kidney might be the primary target organ for CaHV invasion and replication.