title: Outbreak of betanodavirus infection in tilapia, Oreochromis niloticus (L.), in fresh water.
abstract: A betanodavirus associated with a massive mortality was isolated from larvae of tilapia, Oreochromis niloticus, maintained in fresh water at 30 degrees C. Histopathology revealed vacuolation of the nervous system, suggesting an infection by a betanodavirus. The virus was identified by indirect fluorescent antibody test in the SSN1 cell line and further characterized by sequencing of a PCR product. Sequencing of the T4 region of the coat protein gene indicated a phylogenetic clustering of this isolate within the red-spotted grouper nervous necrosis virus type. However, the tilapia isolate formed a unique branch distinct from other betanodavirus isolates. The disease was experimentally reproduced by bath infection of young tilapia at 30 degrees C. The reservoir of virus at the origin of the outbreak remains unidentified. To our knowledge, this is the first report of natural nodavirus infection in tilapia reared in fresh water.
authors.affiliation: Unité de Pathologie Virale des Poissons, AFSSA, Technopôle Brest-Iroise, Plouzané, France. l.bigarre@afssa.fr
authors.forename: L
authors.initials: L
authors.lastname: Bigarré
authors.forename: J
authors.initials: J
authors.lastname: Cabon
authors.forename: M
authors.initials: M
authors.lastname: Baud
authors.forename: M
authors.initials: M
authors.lastname: Heimann
authors.forename: A
authors.initials: A
authors.lastname: Body
authors.forename: F
authors.initials: F
authors.lastname: Lieffrig
authors.forename: J
authors.initials: J
authors.lastname: Castric
mesh_terms: D000818:Animals; D017756:Aquaculture; D001483:Base Sequence; D036022:Capsid Proteins / Q000235:genetics; D004196:Disease Outbreaks / Q000662:veterinary*; D005060:Europe / Q000453:epidemiology; D005393:Fish Diseases / Q000453:epidemiology* / Q000401:mortality / Q000821:virology*; D019084:Fluorescent Antibody Technique, Indirect; D005618:Fresh Water; D008969:Molecular Sequence Data; D030381:Nodaviridae; D012327:RNA Virus Infections / Q000453:epidemiology / Q000401:mortality / Q000662:veterinary*; D017422:Sequence Analysis, DNA; D017210:Tilapia / Q000235:genetics*
chemical_list: D036022:Capsid Proteins