698
Vaccines
The expectation during the 1970s was that vaccines would become the primary
means of disease prevention. Yet in many cases the programmes of research have
not resulted in many commercial products. However, there have been success stories, such as the vaccines for the control of vibriosis (caused by V. anguillarum and
V. ordalii ) and ERM. The research has progressed from the simplistic and often
completely successful approach of using chemically-inactivated whole cell suspensions to purifi ed subcellular antigenic components of pathogens and to live attenuated vaccines.
Historically, the fi rst serious attempt to develop a bacterial fi sh vaccine may be
traced to the work of Duff ( 1942 ), who used chloroform-inactivated cells to protect
cutthroat trout ( Salmo clarki ) against furunculosis. Since then, vaccines have been
formulated against half of the total number of bacterial fi sh pathogens.
Composition of Bacterial Fish Vaccines
The composition of bacterial fi sh vaccines may be categorised as follows:
• Chemically or heat-inactivated whole cells. These vaccines may be mono- or
polyvalent. Essentially, these are the simplest, crudest and cheapest forms of fi sh
vaccines.
• Inactivated soluble cell extracts, i.e. toxoids.
• Cell lysates.
• Attenuated live vaccines, (e.g. LaFrentz et al. 2008 ) possibly geneticallyengineered cells. These would be unacceptable to some regulatory authorities
because of the perceived risk that the vaccine strain may revert to a pathogenic
mode.
• Attenuated live, heterologous vaccines. An example is Bacillus Calmette and
Guèrin (BCG), which is live attenuated Mycobacterium bovis product, protected
Japanese fl ounder against mycobacteriosis (Kato et al. 2010 ).
• Subunit vaccines, e.g. the genes product of the tapA gene for the control of Aer.
salmonicida infections (Nilsson et al. 2006 ).
• DNA vaccines (e.g. Pasnik and Smith 2006 ; Jiao et al. 2009 ; Sun et al. 2010 ).
• Purifi ed sub-cellular components, e.g. glyceraldehyde-3-phosphate dehydrogenase (GAPDH), OMP and LPS. These vaccines require a detailed understanding
of microbial chemistry, aspects of which are defi cient for many of the bacterial
fi sh pathogens.
• Serum, for passive immunisation (e.g. Shelby et al. 2002 ). This is largely of academic interest only, insofar as it is diffi cult to envisage use of the technique in the
fi sh farm environment. A possible exception is for brood stock or pet fi sh.
• Mixtures of the components, detailed above.
14 Control
Vaccines
The expectation during the 1970s was that vaccines would become the primary
means of disease prevention. Yet in many cases the programmes of research have
not resulted in many commercial products. However, there have been success stories, such as the vaccines for the control of vibriosis (caused by V. anguillarum and
V. ordalii ) and ERM. The research has progressed from the simplistic and often
completely successful approach of using chemically-inactivated whole cell suspensions to purifi ed subcellular antigenic components of pathogens and to live attenuated vaccines.
Historically, the fi rst serious attempt to develop a bacterial fi sh vaccine may be
traced to the work of Duff ( 1942 ), who used chloroform-inactivated cells to protect
cutthroat trout ( Salmo clarki ) against furunculosis. Since then, vaccines have been
formulated against half of the total number of bacterial fi sh pathogens.
Composition of Bacterial Fish Vaccines
The composition of bacterial fi sh vaccines may be categorised as follows:
• Chemically or heat-inactivated whole cells. These vaccines may be mono- or
polyvalent. Essentially, these are the simplest, crudest and cheapest forms of fi sh
vaccines.
• Inactivated soluble cell extracts, i.e. toxoids.
• Cell lysates.
• Attenuated live vaccines, (e.g. LaFrentz et al. 2008 ) possibly geneticallyengineered cells. These would be unacceptable to some regulatory authorities
because of the perceived risk that the vaccine strain may revert to a pathogenic
mode.
• Attenuated live, heterologous vaccines. An example is Bacillus Calmette and
Guèrin (BCG), which is live attenuated Mycobacterium bovis product, protected
Japanese fl ounder against mycobacteriosis (Kato et al. 2010 ).
• Subunit vaccines, e.g. the genes product of the tapA gene for the control of Aer.
salmonicida infections (Nilsson et al. 2006 ).
• DNA vaccines (e.g. Pasnik and Smith 2006 ; Jiao et al. 2009 ; Sun et al. 2010 ).
• Purifi ed sub-cellular components, e.g. glyceraldehyde-3-phosphate dehydrogenase (GAPDH), OMP and LPS. These vaccines require a detailed understanding
of microbial chemistry, aspects of which are defi cient for many of the bacterial
fi sh pathogens.
• Serum, for passive immunisation (e.g. Shelby et al. 2002 ). This is largely of academic interest only, insofar as it is diffi cult to envisage use of the technique in the
fi sh farm environment. A possible exception is for brood stock or pet fi sh.
• Mixtures of the components, detailed above.
14 Control