Lampou E, Dovas C, Margaroni M, Chasalevris T, Pappas IS, Dotsika E, Karagouni E, Athanassopoulou F, Katsaras D, Bitchava K. Investigation of routes of entry and dispersal pattern of RGNNV in tissues of European sea bass, Dicentrarchus labrax.
J Fish Dis 2020;
43:1363-1371. [PMID:
32882747 DOI:
10.1111/jfd.13215]
[Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 06/05/2020] [Accepted: 06/08/2020] [Indexed: 06/11/2023]
Abstract
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.
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