Abstract Streptococcus iniae infects a wide range of fish species and causes significant losses in aquaculture. In Japan, commercial vaccines against S. iniae have been approved for use in marine fishes. In this study, we evaluated the efficacy of two commercial vaccines against S. iniae in three freshwater-farmed Oncorhynchus species—rainbow trout O. mykiss , masu salmon O. masou masou , and coho salmon O. kisutch —and examined the role of serum antibodies in vaccine-induced protection. All three species exhibited comparable susceptibility to S. iniae strain TB-0107. In each of the three species, the vaccinated groups showed significantly higher survival rates following S. iniae challenge than the control group, with a relative percentage survival exceeding 90%. The serum antibody titers were found to be significantly elevated in vaccinated fish across all of the species. Furthermore, passive transfer of serum from vaccinated fish conferred enhanced survival in recipients, which may suggest a contribution of antibodies to protection. These results indicate that commercial vaccines against S. iniae are effective in Oncorhynchus species, and that the induction of specific antibodies plays an important role in vaccine efficacy in these fish. Commercial vaccines are expected to prevent the mortality caused by S. iniae infection in Oncorhynchus species.
Morimoto et al. (Fri,) studied this question.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: