Abstract:Aquareoviruses, which belong to a newly identified genus of the family Reoviridae, are agents infecting all kinds of aquatic animals. Grass carp reovirus (GCRV) is a kind of pathogenic virus which causes disease outbreak of Grass carp fingerling in freshwater region of China. In June 2008, a strain virus had been isolated from the samples of visceral organs of the diseased Grass carp with Hemorrhage symptoms from a fish pond at Huzhou City in Zhejiang Province. Sample of diseased Grass carp visceral organs was filtered and was injected into healthy Grass carp fingerlings. Clinical signs of Hemorrhage symptoms of Grass Carp were replicated after five days. Mortality of the sample was 57%. By contrast, the control group fishes were still alive. The sample was continually inoculated onto CIK cells and induced typical cytopathic effect (CPE) was observed. The typical CPE was the same with that induced by the GCRV873 strain. The TCID50 of the isolated virus strain was 108/0.1ml. The visceral organs examined by electron microscopy showed that there were a number of viral particles approximately 71~75 nm in diameter with a sphericity shape. Physicochemically, the isolated strain was not sensitive to chloroform and ether. 436bp nucleotide segment was amplified from the isolated virus strain by reverse transcription polymerase chain reaction (RT-PCR). The nucleic acid sequence of the amplicon had been sequenced. It showed 99% identity with those of GCRV strains in GenBank. All of the evidences indicated that the isolated virus stain was GCRV and was named as HZ2008 isolate.
