title: Ostreid herpesvirus type 1 genomic diversity in wild populations of Pacific oyster Crassostrea gigas from Italian coasts.
abstract: Ostreid herpesvirus 1 (OsHV-1) is a significant pathogen affecting the young Pacific oyster Crassostrea gigas, worldwide. A new variant, OsHV-1 μVar, has been associated with recurrent mortality events in Europe since 2008. Epidemiological data collection is key for global risk assessment; however little is known about health status and genotypes present in European wild oyster beds. Most studies to date have involved only cultivated individuals during mortality events, and reported low genotype diversity. With this study, conducted along the Italian coasts, we investigated for the first time the presence of OsHV-1 in European natural oyster beds. Analysis of three genomic regions revealed the presence of at least nine different genotypes, including two variants close to the OsHV-1 reference, known since the early 1990s but with no European record reported since 2010, and highlights relevant genotype diversity in natural environment. Phylogenetic analysis distinguished two distinct clusters and geographical distribution of genotypes, with the exception of a variant very closely related to the μVar, which appeared the single genotype present in all the Adriatic sites. Interestingly, these wild symptom free populations could represent, in Europe, an accessible alternative to the import of OsHV-1-resistant oyster strains from the East Pacific, the native area of C. gigas, avoiding the high-risk of non-native marine species and new pathogen introductions.
authors.affiliation: Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Torino, Italy; Department of Veterinary Medical Sciences, Alma Mater Studiorum, Università di Bologna, Ozzano dell'Emilia, BO, Italy. Electronic address: erika.burioli@izsto.it.
authors.forename: E A V
authors.initials: EAV
authors.lastname: Burioli
authors.affiliation: Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Torino, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Prearo
authors.affiliation: Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Torino, Italy.
authors.forename: M V
authors.initials: MV
authors.lastname: Riina
authors.affiliation: Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Torino, Italy.
authors.forename: M C
authors.initials: MC
authors.lastname: Bona
authors.affiliation: Department of Veterinary Medical Sciences, Alma Mater Studiorum, Università di Bologna, Ozzano dell'Emilia, BO, Italy.
authors.forename: M L
authors.initials: ML
authors.lastname: Fioravanti
authors.affiliation: Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro, PD, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Arcangeli
authors.affiliation: Laboratoire Frank Duncombe LABEO, Caen, France.
authors.forename: M
authors.initials: M
authors.lastname: Houssin
mesh_terms: D000818:Animals; D049896:Crassostrea / Q000821:virology*; D004279:DNA, Viral / Q000032:analysis; D005814:Genes, Viral; D005838:Genotype; D006564:Herpesviridae / Q000235:genetics*; D006566:Herpesviridae Infections / Q000662:veterinary*; D007558:Italy; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D015995:Prevalence; D017422:Sequence Analysis, DNA
chemical_list: D004279:DNA, Viral
keywords: Bivalves; Crassostrea gigas; Ostreid herpesvirus-1; Variants; Wild population