A novel divergent group of Ostreid herpesvirus 1 μVar variants associated with a mortality event in Pacific oyster spat in Normandy (France) in 2016

• Published in: Journal of Fish Diseases
• Main Authors: Burioli, Erika A.V., Varello, Katia, Lavazza, Antonio, Bozzetta, Elena, Prearo, Marino, Houssin, Maryline
• Other Authors: LABÉO, Pôle d’analyses et de recherche de Normandie (LABÉO), Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta (IZSTO), Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna (IZSLER), Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2018
• Subjects: genome evolution; Herpesvirales; mollusc pathology; OsHV-1; phylogenetic analysis; [SDV.BA.MVSA]Life Sciences [q-bio]/Animal biology/Veterinary medicine and animal Health; [SDV.MP.VIR]Life Sciences [q-bio]/Microbiology and Parasitology/Virology; [SDV.SA.ZOO]Life Sciences [q-bio]/Agricultural sciences/Zootechny; Pacific; Pacific oyster
• Online Access: https://hal-normandie-univ.archives-ouvertes.fr/hal-03400584; https://doi.org/10.1111/jfd.12883

International audience The acute course of disease in young oysters infected by OsHV-1 and the rapid tissue degradation often preclude histological examination of specimens collected during outbreaks in field. Herein, live spat originated from two geographical areas were sampled just at the onset of a mortality event that occurred in Normandy (France) in June 2016. The lesions, associated with high OsHV-1 DNA quantities, were characterized by severe and diffuse haemocytosis mainly involving blast-like cells, myocyte degeneration and large, irregularly shaped degenerate eosinophilic cells in the connective tissue. The herpesvirus was identified by negative staining TEM and real-time PCR. Sequencing of the C region and ORFs 42/43 confirmed that the variants met the definition of OsHV-1 μVar. We sequenced 30 other ORFs in twenty OsHV-1-positive individuals and compared them to the μVar specimens isolated between 2009 and 2011. The ORFs encoding putative membrane proteins