Viral encephalopathy and retinopathy (VER) is a serious neuropathological fish disease affecting in the Mediterranean aquaculture mainly European sea bass, Dicentrarchus labrax. It is well known that betanodaviruses are neurotropic viruses that replicate in nerve tissues, preferentially brain and retina. However, routes of entry and progression of the virus in the central nervous system (CNS) remain unclear. The role of four tissues—eye, oesophagus, gills and skin—as possible gateways of a betanodavirus, the redspotted grouper nervous necrosis virus (RGNNV), was investigated after experimental challenges performed on European seabass juveniles. The dispersal pattern of Betanodavirus at primarily stages of the disease was also assessed, using a real‐time qPCR assay. The development of typical clinical signs of VER, the presence of characteristic histopathological lesions in the brain and retina and the detection of viral RNA in the tissues of all experimental groups ascertained that successful invasion of RGNNV under all experimental routes was achieved. Transneuronal spread along pathways known to be connected to the initial site of entry seems to be the predominant scenario of viral progression in the CNS. Furthermore, viraemia appeared only after the installation of the infection in the brain.

中文翻译：

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RGNNV在欧洲鲈鱼Dicentrarchus labrax组织中的进入和扩散方式的研究。

病毒性脑病和视网膜病（VER）是一种严重的神经病理鱼病，主要影响欧洲水鲈，欧洲鲈鱼Dicentrarchus labrax。众所周知，贝塔诺达病毒是在神经组织，优选在大脑和视网膜中复制的嗜神经病毒。但是，该病毒在中枢神经系统（CNS）中的进入和传播途径仍不清楚。眼睛，食道，g和皮肤这四个组织的作用可能是红斑石斑鱼坏死性坏死病毒贝坦诺达病毒的门户（RGNNV）是在对欧洲鲈鱼幼鱼进行实验性挑战后进行调查的。使用实时qPCR测定法还评估了Betanodavirus在疾病主要阶段的传播方式。VER的典型临床体征的发展，脑和视网膜中特征性组织病理学病变的存在以及所有实验组组织中病毒RNA的检测确定了在所有实验途径下RGNNV的成功入侵。沿已知与进入的最初部位相关的途径的跨神经元扩散似乎是CNS中病毒进展的主要情况。此外，病毒血症仅在脑部感染增加后才出现。