Salinity influences disease-induced mortality of the oyster Crassostrea gigas and infectivity of the ostreid herpesvirus 1 (OsHV-1)

• Published in: Aquaculture Environment Interactions
• Main Authors: Fuhrmann, Marine, Petton, Bruno, Quillien, Virgile, Faury, Nicole, Morga, Benjamin, Pernet, Fabrice
• Other Authors: Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire de Génétique et Pathologie (LGP), Unité Amélioration génétique, Santé animale et Environnement (AGSAE), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), ANR-12-AGRO-0001,GIGASSAT,Adaptation des écosystèmes ostréicoles au changement global(2012)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2016
• Subjects: herpes-virus; Herpesviridae; haplosporidium-nelsoni msx; Infection; mu-var; bivalve; bivalve mollusks; Disease transmission; environments; host; Pacific oysters; parasite; pcr; Risk analysis; transmission; ACL; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; Crassostrea gigas
• Online Access: https://hal.science/hal-01483190; https://doi.org/10.3354/aei00197

International audience Mortality of young Pacific oysters Crassostrea gigas associated with the ostreid herpesvirus 1 (OsHV-1) is occurring worldwide. Here, we examined for the first time the effect of salinity on OsHV-1 transmission and disease-related mortality of C. gigas, as well as salinity-related effects on the pathogen itself. To obtain donors for OsHV-1 transmission, we transferred laboratory-raised oysters to an estuary during a disease outbreak and then back to the laboratory. Oysters that tested OsHV-1 positive were placed in seawater tanks (35%, 21 degrees C). Water from these tanks was used to infect naive oysters in 2 experimental setups: (1) oysters acclimated or non-acclimated to a salinity of 10, 15, 25 and 35% and (2) oysters acclimated to a salinity of 25%; the latter were exposed to OsHV-1 water diluted to a salinity of 10 or 25%. The survival of oysters exposed to OsHV-1 water and acclimated to a salinity of 10% was \textgreater 95%, compared to only 43 to 73% survival in oysters acclimated to higher salinities (Expt 1), reflecting differences in the levels of OsHV-1 DNA and viral gene expression (Expts 1 and 2). However, the survival of their non-acclimated counterparts was only 23% (Expt 2), and the levels of OsHV-1 DNA and the expression of 4 viral genes were low (Expt 1). Thus, OsHV-1 may not have been the ultimate cause of mortality in non-acclimated oysters weakened by a salinity shock. It appears that reducing disease risk by means of low salinity is unlikely in the field.