title: Detection and description of a particular Ostreid herpesvirus 1 genotype associated with massive mortality outbreaks of Pacific oysters, Crassostrea gigas, in France in 2008.
abstract: Ostreid herpesvirus 1 (OsHV-1) infections have been reported around the world and are associated with high mortalities of the Pacific oyster (Crassostrea gigas). In the summer 2008, abnormal mortality rates ranging from 80% to 100% were reported in France and affected only Pacific oysters. Analyses of oyster samples collected during mortality outbreaks demonstrated a significant detection of OsHV-1 (75% of analysed batches), which appeared stronger than previous years. DNA sequencing based on C and IA regions was carried out on 28 batches of OsHV-1 infected Pacific oysters collected in 2008. Polymorphisms were described in both the C and IA regions and characterized a genotype of OsHV-1 not already reported and termed OsHV-1 microVar. A microsatellite zone present in the C region showed several deletions. Additionally, 44 isolates collected in France and in the USA, from 1995 to 2007 were sequenced and compared to the 2008 sequences. The analyses of 76 sequences showed OsHV-1 microVar detection only in 2008 isolates. These data suggest that OsHV-1 microVar can be assumed as an emergent genotype.
authors.affiliation: Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire de Génétique et Pathologie (LGP), Avenue de Mus de Loup, 17390 La Tremblade, France.
authors.forename: Amélie
authors.initials: A
authors.lastname: Segarra
authors.forename: Jean François
authors.initials: JF
authors.lastname: Pépin
authors.forename: Isabelle
authors.initials: I
authors.lastname: Arzul
authors.forename: Benjamin
authors.initials: B
authors.lastname: Morga
authors.forename: Nicole
authors.initials: N
authors.lastname: Faury
authors.forename: Tristan
authors.initials: T
authors.lastname: Renault
mesh_terms: D000818:Animals; D001483:Base Sequence; D049896:Crassostrea / Q000821:virology*; D004279:DNA, Viral / Q000737:chemistry / Q000235:genetics*; D005602:France; D005838:Genotype; D006564:Herpesviridae / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D018895:Microsatellite Repeats; D008969:Molecular Sequence Data; D010802:Phylogeny; D011110:Polymorphism, Genetic; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D017385:Sequence Homology; D014481:United States
chemical_list: D004279:DNA, Viral