Biotechnology and Bioinformatics (1+1)

4.3.14. Environmental, ethical and regulatory aspects of fish immunization

Preventive immunization coupled with good management is obviously the most suitable means of fish disease control in intensive aquaculture.

• An ideal vaccine suitable for large-scale usage should be highly immunogenic, should offer a long-term protection, be cost effective, easy to produce and deliver and should be safe. It should meet all the safety and regulatory criteria before being used for field application.
• Although some vaccines meet many of the important attributes necessary for a good vaccine, the problem of environmental, ethical and regulatory aspects of field application still remain as an obstacle for their large-scale usage.
• This is obvious in the case of live-attenuated vaccines (both conventional and gene tically engineered) and DNA vaccines.
• Live vaccines, although are highly immunogenic, remains unattractive for long time for field application because of the apprehension of their reversion to pathogenic state and the chance of the vaccine strain becoming pathogenic to non-target species.
• Additionally, there is fear of shedding and persistence of live vaccine strains in tissues.

DNA vaccines are argued to pose many dangers to target animals such as:

• potential integration of plasmid DNA into the genome of the host cells,
• potential induction of immune tolerance or of autoimmunity and
• the potential induction of antibodies to the injected plasmid DNA.