Farm fish vaccination

Abstract

Fish, at least teleosts, are equipped with an immune system similar to that of terrestrial vertebrates. It is divided into two main systems,the innate or non-specific system and the adaptive system, specific to the pathogen. Fish are able to recognize an antigen and to developa specific immune response. Thus, it is possible to vaccinate them. Fish can be immunized using several ways including injection, balneationand oral administration. Various types of vaccines exist : inactivated vaccines which are essentially anti-bacterial vaccines producedby bacteria fermentation followed by an inactivation with formalin, and live attenuated vaccines, which were initially especially studiedwith respect to viral diseases in order to try to compensate for the deficiency of the killed vaccines. Although effective by balneation, theyare not marketed because they are not compatible with veterinary and environmental control strategies. Lastly, with the development ofmolecular biology, new types of vaccines are under development in fish like the recombinant subunit vaccines whose effectiveness has,however, not been shown. On the contrary, the results with DNA vaccines are very promising and the latter should, in a near future, optimizefish vaccination.