Vaccines and integrated prevention in aquaculture (Part 2)

Abstract

The second part of this review addresses current approaches to specific immunoprophylaxis and the design of integrated programs for preventing infectious diseases in fish. Major vaccine platforms used or investigated in aquaculture are systematized, including inactivated, live attenuated, subunit, recombinant, DNA, RNA, vector-based and mucosal vaccines. Bacterial and viral targets are analyzed together with experimental strategies aimed at Saprolegnia parasitica and Aphanomyces invadans. Injection, immersion and oral delivery routes are discussed, as well as adjuvants, nanoparticles and biological antigen-delivery systems. Particular attention is given to probiotics as immunological and technological partners of vaccination, including pre-vaccination conditioning, post-vaccination support, probiotic microorganisms as antigen carriers, and combined seasonal prevention schemes. Safety requirements, regulatory considerations and evidence-based assessment are reviewed. A practical model of integrated prevention is presented, combining risk audit, diagnostics, biosecurity, vaccination, microbiota management, nutrition and outcome monitoring. The analysis shows that the strongest preventive effect is achieved not by opposing vaccines and probiotics, but by integrating pathogen-specific immunization with microbiota-oriented and technology-based interventions tailored to the production system.