Email updates

Keep up to date with the latest news and content from BMC Veterinary Research and BioMed Central.

Open Access Highly Accessed Research article

Viral Encephalopathy and Retinopathy in groupers (Epinephelus spp.) in southern Italy: a threat for wild endangered species?

Niccolò Vendramin12, Pierpaolo Patarnello4, Anna Toffan1*, Valentina Panzarin1, Elisabetta Cappellozza1, Perla Tedesco3, Antonio Terlizzi3, Calogero Terregino1 and Giovanni Cattoli1

Author Affiliations

1 Istituto Zooprofilattico Sperimentale delle Venezie, viale dell’Università, 10-35020, Legnaro, Padova, Italy

2 Current affiliation: EURL for fishdiseases, DTU VET, Hangovej 2, Aarhus, Denmark

3 Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, Università del Salento, CoNISMa, Lecce, Italy

4 Fish Patologist, Private Expert, Istituto Zooprofilattico Sperimentale delle Venezie, viale dell’Università, 10 -35020 Legnaro, Padova, Italy

For all author emails, please log on.

BMC Veterinary Research 2013, 9:20  doi:10.1186/1746-6148-9-20

Published: 26 January 2013

Abstract

Background

Betanodaviruses are the causative agents of Viral Encephalopathy and Retinopathy (VER). To date, more than 50 species have proved to be susceptible and among them, those found in genus Epinephelus are highly represented. Clinical disease outbreaks are generally characterized by typical nervous signs and significant mortalities mainly associated with aquaculture activities, although some concerns for the impact of this infection in wild fish have been raised. In this study, the authors present the first documented report describing an outbreak of VER in wild species in the Mediterranean basin.

Case presentation

In late summer - early winter 2011 (September-December), significant mortalities affecting wild Dusky grouper (Epinephelus marginatus), Golden grouper (Epinephelus costae) and European sea bass (Dicentrarchus labrax) were reported in the municipality of Santa Maria di Leuca (Northern Ionian Sea, Italy). The affected fish showed an abnormal swimming behavior and swollen abdomens. During this epizootic, five moribund fish showing clear neurological signs were captured and underwent laboratory investigations. Analytical results confirmed the diagnosis of VER in all the specimens. Genetic characterization classified all betanodavirus isolates as belonging to the RGNNV genotype, revealing a close genetic relationship with viral sequences obtained from diseased farmed fish reared in the same area in previous years.

Conclusion

The close relationship of the viral sequences between the isolates collected in wild affected fish and those isolated during clinical disease outbreaks in farmed fish in the same area in previous years suggests a persistent circulation of betanodaviruses and transmission between wild and farmed stocks. Further investigations are necessary to assess the risk of viral transmission between wild and farmed fish populations, particularly in marine protected areas where endangered species are present.

Keywords:
Viral Encephalopathy and Retinopathy; Betanodavirus; Neurological signs; Wild fish; Epinephelus spp.