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 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 - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire de Génétique et Pathologie (LGP), 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: ACL; transmission; host; Pacific oysters; Infection; mu-var; bivalve; bivalve mollusks; Disease transmission; environments; haplosporidium-nelsoni msx; Herpesviridae; herpes-virus; parasite; Risk analysis; pcr; envir; geo; Pacific; Crassostrea gigas
• Online Access: https://doi.org/10.3354/aei00197; https://hal.archives-ouvertes.fr/hal-01483190

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.