Submitted to: Catfish Farmers of America Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: December 15, 2008
Publication Date: March 6, 2009
Citation: Shoemaker, C.A., Klesius, P.H., Evans, J.J. 2009. Modified Live Flavobacterium columnare Vaccine. 2009 Catfish Farmers of America Research Symposium. p. 8. Technical Abstract: Flavobacterium columnare is an aquatic bacterium that is highly infectious in both warm and cold water species of fish. In the channel catfish (Ictalurus punctatus) industry it causes columnaris disease and has a significant impact on production (~$30 million annually). Development of a successful vaccine against columnaris required the vaccine to be safe and easily administered to young fish. The vaccine also needed to stimulate protective immunity of long duration. We developed a modified F. columnare isolate by passage on an antibiotic (rifampicin). Changes in the lipopolysaccharide (LPS) profile were shown by immunoblots that revealed the higher molecular weight bands of LPS were absent in the rifampicin modified isolate. Interestingly, anti-serum generated in channel catfish from the vaccine isolate (genomovar I) or from a genomovar II isolate (ALG-530) cross reacted in immunoblots with the LPS and whole cell lysate proteins of either type I or type II isolates suggesting that the core antigens are conserved. The modified F. columnare was attenuated and did not cause disease. In vivo reversion to virulence studies (back-passage studies) demonstrated the vaccine to be safe at ten times the normal immunization dose in 10 day post hatch channel catfish fry. Efficacy of the modified live F. columnare vaccine was demonstrated in 10 and 48 day post hatch and 3 month old channel catfish (RPS from 71-94%). Vaccine efficacy has also been demonstrated in eyed channel catfish eggs immunized 24 to 48 hours prior to hatching. Relative percent survivals ranged from 50-77 % following challenge of the resulting immunized fry at greater than 100 days post vaccination. Intervet, Inc., licensed the vaccine from USDA-ARS (CRADA), obtained USDA-APHIS-CVB approval and is marketing the vaccine under the trade name AQUAVAC-COL™ .