Pathogenicity of the Nodavirus Detected from Diseased Sevenband Grouper Epinephelus septemfasciatus.

Immune response to a recombinant capsid protein of striped jack nervous necrosis virus (SJNNV) in turbot Scophthalmus maximus and Atlantic halibut Hippoglossus hippoglossus, and evaluation of a vaccine against SJNNV

“…Although the observed differences were not statistically significant, the results may indicate that the severity of VER in turbot increases with a rise in water temperature. A similar temperature-dependent effect after challenge with nodavirus has been indicated in other species , Tanaka et al 1998, Chi et al 1999.In the present study mortality was not recorded in turbot after bath exposure to SJNNV, even though a high virus titre was employed. Similar results were obtained in redspotted grouper Epinephelus akaara that were bath challenged with a nodavirus strain from sevenband grouper.…”

“…As opposed to other modes of challenge, intramuscular inoculation has been shown both in our study and in others (Tanaka et al 1998, Péducasse et al 1999) to elicit more severe disease and higher mortality. Thus, vaccine efficacy tests for nodavirus employing intramuscular inoculation probably offer a strict evaluation of vaccine protection, and equivalent or better protection would be expected under field conditions.…”

“…Because mortality in the unvaccinated fish was higher than in either rT2-vaccinated or controlvaccinated fish, it is likely that the adjuvant by itself offers protection against challenge, possibly through non-specific stimulation of the immune system. This effect appears to last at least until 10 wk post-vaccination, probably due to a slow release of adjuvant from depots.As opposed to other modes of challenge, intramuscular inoculation has been shown both in our study and in others (Tanaka et al 1998, Péducasse et al 1999) to elicit more severe disease and higher mortality. Thus, vaccine efficacy tests for nodavirus employing intramuscular inoculation probably offer a strict evaluation of vaccine protection, and equivalent or better protection would be expected under field conditions.…”

“…Similar results were obtained in redspotted grouper Epinephelus akaara that were bath challenged with a nodavirus strain from sevenband grouper. No mortality was recorded but some fish showed symptoms of VER (Tanaka et al 1998). In contrast, European sea bass bath challenged with a nodavirus isolate from the sea bass (500 pfu ml -1 ) experienced 32% mortality (Péducasse et al 1999).…”

Betanodavirus of Marine and Freshwater Fish: Distribution, Genomic Organization, Diagnosis and Control Measures

“…To control the infections, it is important to understand the epidemiology and pathogenic mechanisms of the virus. Betanodavirus infection can be influenced by host factors such as age [1,3], environmental factors such as water temperature [106,115,125] and other stress factors such as suboptimal feed, suboptimal water quality, crowding, transport and repeated spawning of broodstock [55,64,84,115]. The virus can be transmitted both horizontally [15,49,71,99] and vertically [2,7,14,49,83,84,92,102,119].…”