Submitted to: Symposium Diseases in Asian Aquaculture Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: August 22, 2005
Publication Date: October 25, 2005
Citation: Klesius, P.H., Shoemaker, C.A., Evans, J.J. 2005. Attenuated vaccines against gram-negative bacterial pathogens. 6th Symposium on Diseases in Asian Aquaculture Proceedings. Colombo Plaza Hotel, Colombo, Sri Lanka. October 25-28, 2005. Technical Abstract: Prevention of fish diseases is becoming more dependent on the use of vaccines. An important consideration is what type of vaccine to use: attenuated or a killed vaccine? The choice of the vaccine type needs to be compatible with production system and growth life cycle of the fish species. Also, the choice needs to be compatible with method of administration and the duration of protection. The best type of vaccine is one that is cost-effectively administered to large numbers of the youngest life-stage of fish with no or minimal stress. Attenuated vaccines fulfill these needs. Modified live vaccines against Edwardsiella ictaluri and Flavobacterium columnare are used in 7-10 day post-hatched catfish fry by immersion exposure for 2 minutes. The vaccines are as AQUAVAC-ESC and AQUAVAC-COL (Intervet) for protection against enteric septicemia of catfish (ESC) and columnaris (COL), respectively. Vaccinated fish have higher survival rates (75 to 90%) against both ESC and COL, respectively. Finally, attenuated vaccines offer a number of advantages over the less efficacious and cost-ineffective killed vaccines for the aquaculture industry.