Efficacy of a modified live Flavobacterium columnare vaccine in fish

摘要

Flavobacterium columnare is an aquatic bacterium that is responsible for columnaris disease. This aquatic pathogen has a worldwide distribution and is highly infectious to both warm and cold water fish. Aaamodified live F. columnare vaccine was developed by repeated passage of a virulent strain on increasing concentrations of rifampicin that resulted in attenuation. Here we report vaccination/challenge trials to evaluate efficacy and safety. In separate laboratory trials, immersion vaccination of channel catfish (Ictalurus punctatus) fry between 10 to 48 days post hatch (DPH) with experimental vaccine or licensed product resulted in relative percent survival (RPS) between 57-94% following challenge. Similarly, a vaccination/challenge trial using largemouth bass (Micropterus salmoides) fry at 10 DPH was performed using various doses of licensed product under laboratory conditions. Results demonstrated safety of the vaccine and significant protection following challenge with RPS values between 74-94%, depending on vaccine dose. Together, these trials demonstrate the vaccine administered to early life-stage channel catfish and largemouth bass is safe and reduces mortality following challenge with F. columnare. a-[ordm Flavobacterium columnare is an aquatic bacterium causing columnaris disease in fish. a-[ordm Laboratory efficacy of a modified live F. columnare vaccine was evaluated. a-[ordm The vaccine was delivered to young fish (7-48 days post hatch) by immersion. a-[ordm The modified live F. columnare vaccine protected largemouth bass and channel catfish.