草鱼出血病两种病原病毒的分离和致病性的研究

通过PEG和鱼精蛋白沉淀等方法,从草鱼(Ctenopharynogon idellus)出血病病鱼组织分离纯化出两种病毒.一种是直径70—80nm的病毒颗粒,六边形,有双层衣壳,无囊膜;另一种直径仅20—30nm的小病毒颗粒,也呈六边形.前者是呼肠孤病毒(Reovirus),以前已有报道;后者拟初步鉴别为小RNA病毒科(Picornaviridae)病毒.将两者分别感染1足龄健康草鱼,能复制出典型症状的草鱼出血病而致鱼死亡.呼肠孤病毒主要导致肠道出血的出血病,而小病毒颗粒导致肌肉出血为主的出血病.由此可以初步解释生产上出现两类出血病的原因.

Studies on the Isolation and Pathogenicity of Two Kinds of Hemorrhagic Virus of Grass Carp,Ctenopharynogodon idellus

Two different kinds of pathogenic virus were isolated from the tissue of fish suffering from Hemorrhage of Grass Carp by means of PEG and prota-mine sedimentation. One kind of virosome is larger in size with 70-80 nm in diameter. It shows hexagon with a double capsid structure and with an electron dense core under electron microscope.Another kind of virus is smaller with 20-30 nm in diameter. It exhibits a shape of hexagon. According to the morphologic observation and nucleic acid qualitative determination, they are considered to be the member of Reovirus and Picornaviridae respectively. The two kinds of purified virus suspension were used to infect Grass Carp fingerlings separately and typical symptoms of Hemorrhage of Grass Carp can be replicated. The fish were affected to death in result. The Hemorrhage morbidity of Reovirus was 66.13% and that of Picornaviridae virus 64%. It shows that the two kinds of virus were both the causative agents of Hemorrhage of Grass Carp. The main pathological feature of Reovirus was Hemorrhage of intestinal tract, and the other one was Hemorrhage of musculature.