Dapeng Yu, Tingting Weng, Hongli Xia, Liqun Xia, Yishan Lu, Zhiwen Wang, Jia Cai
Nervous necrosis virus (NNV) is a viral pathogen that infected variety of cultured and farmed fish around the world. In this study, we isolated a novel NNV from diseased cultured tilapia (Oreochromis niloticus). The typical vacuolates were discovered in the brain of diseased tilapia through histological analysis. The virus was identified as NNV with RT-PCR tested of brain tissues and named as ONNV-ZS. In addition, the virus was purified by incubating GS cells with tissue suspension of brain from diseased O. niloticus. The obvious CPE (cytopathic effect) was observed in infected cells and the virus was confirmed by RT-PCR. Electron microscopy of the infected cells revealed the virus particles with non-enveloped spherical shape. The pathogenicity of ONNV-ZS was explored in challenge experiments using O. niloticus juveniles. The cumulative mortalities reached 100% at day 10 post-infection. Together, this is the first report for isolation and identification of a NNV isolate from O. niloticus in China.