Submitted to: Aquaculture America Conference
Publication Type: Abstract Only
Publication Acceptance Date: December 13, 2005
Publication Date: February 16, 2006
Citation: Klesius, P.H., Shoemaker, C.A., Evans, J.J. 2006. Modified live vaccines for gram negative pathogens of catfish. Aquaculture America Conference 2006. Las Vegas, Nevada. Febrauary 13-16, 2006. page 153. Technical Abstract: Vaccines, adjuvants and immunostimulants encompass a variety of biological compounds capable of producing immune responses against aquatic animal pathogens. The prevention of diseases is becoming more dependent on the use of immunobiologics in aquatic animals, especially vaccines in fish. An important consideration in whether to vaccinate is cost effectiveness to producers compared to other means of disease control. The decision to use a vaccine may be answered by will the producer make a greater profit following vaccination after factoring in vaccine and vaccination costs? However, the risks of not using a vaccine may be a more significant factor when faced with the total loss of profits even when minor-moderate disease outbreaks occur. The choice of the vaccine 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. In the catfish industry, the best type of vaccine is one that is cost-effectively administered to large numbers (i.e. mass vaccination) of the youngest life-stage of fish with no or minimal stress. Modified live vaccines fulfill these needs for the catfish industry. Modified live or attenuated vaccines against Gram-negative catfish pathogens meet or exceed the vaccinology requirements of the catfish industry. Modified live vaccines against Edwardsiella ictaluri and Flavobacterium columnare are fully licensed for use in 7-10 day post-hatched catfish fry by immersion exposure for 2 minutes. The USDA, Agricultural Research Service vaccines were licensed to Intervet and marketed under the trade name AQUAVAC-ESC and AQUAVAC-COL for protection against enteric septicemia of catfish (ESC) and columnaris (COL), respectively. Intervet estimated that economic benefit to the producer is $1,706 per acre over non-vaccinated catfish. Intervet reported that vaccinated catfish continue to eat more during the fall and spring ESC season and typically gain over 1 inch more than non-vaccinated catfish. The vaccinated fish have higher survival rates against both ESC and COL. In addition, the ESC vaccine can be used to vaccinate eyed catfish eggs and protects the fingerlings against ESC. Thus, modified live vaccines offer a number of advantages over the less efficacious and cost-ineffective killed vaccines for the catfish industry.