Flavobacterium psychrophilum is a bacteria which causes cold-water disease in trout, especially in the aquaculture industry. Infection of trout and other fishes with this bacteria leads to mortality rates from 18% to 30% and significant economic loss. To date, there is no effective vaccine for prevention of this disease. The purpose of this study is to develop an effective and economic vaccine for the prevention of cold-water disease. OBJECTIVES: The objective of this proposal is to demonstrate the feasibility of utilizing bacteria killed using novel methods as vaccines for aquaculture. Current vaccination strategies for the prevention of aquaculture diseases utilize traditional killing technologies including chemical or heat inactivation of cultured pathogens or live attenuated strains of pathogens. While some of these vaccines have proved to be efficacious, others have demonstrated sub-par immunogenicity and protection which may be due, in part, to the destruction of immunogenic epitopes by the killing mechanism. In this proposal a killing mechanism which does not alter immunogenic epitopes will be used to develop a vaccine for Flavobacterium psychrophilum. To date, there is no effective vaccine against this pathogen and development of such a vaccine is of great importance to the cold water aquaculture industry. APPROACH: To demonstrate feasibility, Flavobacterium psychrophilum, the etiologic agent of cold water disease, will be used. First a system of plasmid constructs will be developed which replicate and promote expression of proteins within F. psychrophilum. Then, a bacterial killing mechanism, encoded on the plasmid construct, will be utilized to inactivate the organism. The inactivated organisms will then be used in efficacy trials in trout. The long-term goal of this project is to develop a safe and effective vaccine for commercialization and marketing to the aquaculture community
