INTEGRATED AQUATIC ANIMAL HEALTH STRATEGIES
Location: Aquatic Animal Health Research
Title: Vaccination of fish against Flavobacterium columnare and F. psychrophilum
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: September 25, 2012
Publication Date: October 1, 2012
Citation: Lafrentz, B.R., Cain, K.D., Shoemaker, C.A., Klesius, P.H. 2012. Vaccination of fish against Flavobacterium columnare and F. psychrophilum [abstract]. US-Russia Workshop on Aquaculture and Fish Health. p. 17.
There are two primary Flavobacterium spp. involved in disease of aquaculture raised fish worldwide including, F. columnare, and F. psychrophilum; the etiologic agents of columnaris disease and bacterial coldwater disease (CWD) or rainbow trout fry syndrome (RTFS), respectively. Traditional vaccines based on killed whole-cells (i.e., bacterins) have not been effective at preventing losses due to these diseases, thus research was initiated to determine whether modified live vaccines may be more effective. An attenuated strain of F. columnare was generated by repeat passage of the bacterium on agar plates containing increasing concentrations of the antibiotic rifampicin. Laboratory experiments demonstrated the safety and efficacy of the vaccine in channel catfish Ictalurus punctatus and largemouth bass Micropterus salmoides. The vaccine was licensed by Intervet, Inc. (now Merck Animal Health) in 2005 for use in channel catfish in the USA. Given the success of the modified live F. columnare vaccine, a similar strategy was used with F. psychrophilum. A virulent isolate, 259-93, was passed on increasing concentrations of rifampicin. One resultant strain, B.17, was demonstrated to be highly attenuated in rainbow trout Oncorhynchus mykiss. Initial studies demonstrated relative percent survival (RPS) values of up to 45% following immunization of rainbow trout with the modified live B.17 strain by injection and immersion delivery. Subsequent studies have demonstrated efficacy of the vaccine in Coho salmon O. kisutch by both injection and immersion delivery methods, with RPS values of up to 98 and 73%, respectively. Furthermore, culture of the vaccine in iron-limited media enhanced vaccine efficacy. A partnership with a private company has been established and trials are underway to determine the safety and efficacy of the modified live F. psychrophilum vaccine under field conditions.