517
salmonicida has caused mortalities in cod (Jørgensen et al. 1989 ). The plasmids,
which are regarded as being present in all strains, do not appear to be related to virulence (Valla et al. 1992 ). Using isolated macrophages from Atlantic salmon and rainbow trout with immunofl uorescence techniques, the pathogen has been observed to
be internalised (Brattgjerd et al. 1995 ). The pathogen has been found to express a
luciferase, but does not produce detectable luminescence. Yet, there appears to be an
association between a mutation in the lux gene and virulence (Nelson et al. 2007 ).
The pathogen has the ability to adhere to mucosal surfaces, (Ræder et al. 2007 )
i.e. foregut, gills, hindgut, pyloric caeca and skin (Knudsen et al. 1999 ). Indeed,
there is evidence that skin is the major route of infection (Kashulin and Sørum
2014 ). In the presence of fi sh mucus, there was evidence of increased levels of Ali.
salmonicida proteins notably those fl agellin and those involved with oxidative[peroxidase] and general [heat shock protein and chaperonin] stress responses
(Ræder et al. 2007 ).
What about the risk of disease after transferring salmon from fresh to seawater?
Eggset et al. ( 1997 ) concluded that the susceptibility of Atlantic salmon to Hitra
disease in seawater possibly refl ected the overall quality of the smolts.
Disease Control
Disease Resistant Fish Gjedrem and Aulstad ( 1974 ) noted signifi cant variation in
resistance among strains of Atlantic salmon.
Vaccine Development There has been success with vaccines for the prophylaxis
of Hitra disease, with the protective antigen possibly including the presence of a
20 kDa peptidoglycan-associated lipoprotein, Pal (Karlsen et al. 2011 ). Immersion
of Atlantic salmon in vaccine preparations resulted in protection, even after 6
months (Holm and Jørgensen 1987 ). It has emerged that Ali. salmonicida vaccines
exert adjuvant activities on T-dependent and T-independent antigens in salmonids,
namely rainbow trout. Essentially, vaccine preparations enhance antibody responses
notably to LPS (Steine et al. 2001 ). Thus, the inclusion of inactivated Ali. salmonicida antigens in vaccines preparations may have an overall benefi cial effect on the
recipient fi sh (Hoel et al. 1998 ). The incubation temperature used to culture Ali.
salmonicida is an important aspect of vaccine production with 10 °C (this coincides
with the upper range of water temperatures at which coldwater vibriosis is most
likely to occur) rather than 15 °C giving a higher yield of cells in broth media
(Colquhoun et al. 2002 ).
At least one vaccine has been commercialised in a polyvalent form.
Immunostimulants/Dietary Supplements Synergism between low levels of iron
and high amounts of long-chain polyunsaturated fatty acids led to and RPS 96 %
after challenge with Ali. salmonicida (Rørvik et al. 2003 ). Carvacrol, which in part
of the essential oil of plants including oregano ( Origanum vulgare ) was fed at
Aliivibrio salmonicida
salmonicida has caused mortalities in cod (Jørgensen et al. 1989 ). The plasmids,
which are regarded as being present in all strains, do not appear to be related to virulence (Valla et al. 1992 ). Using isolated macrophages from Atlantic salmon and rainbow trout with immunofl uorescence techniques, the pathogen has been observed to
be internalised (Brattgjerd et al. 1995 ). The pathogen has been found to express a
luciferase, but does not produce detectable luminescence. Yet, there appears to be an
association between a mutation in the lux gene and virulence (Nelson et al. 2007 ).
The pathogen has the ability to adhere to mucosal surfaces, (Ræder et al. 2007 )
i.e. foregut, gills, hindgut, pyloric caeca and skin (Knudsen et al. 1999 ). Indeed,
there is evidence that skin is the major route of infection (Kashulin and Sørum
2014 ). In the presence of fi sh mucus, there was evidence of increased levels of Ali.
salmonicida proteins notably those fl agellin and those involved with oxidative[peroxidase] and general [heat shock protein and chaperonin] stress responses
(Ræder et al. 2007 ).
What about the risk of disease after transferring salmon from fresh to seawater?
Eggset et al. ( 1997 ) concluded that the susceptibility of Atlantic salmon to Hitra
disease in seawater possibly refl ected the overall quality of the smolts.
Disease Control
Disease Resistant Fish Gjedrem and Aulstad ( 1974 ) noted signifi cant variation in
resistance among strains of Atlantic salmon.
Vaccine Development There has been success with vaccines for the prophylaxis
of Hitra disease, with the protective antigen possibly including the presence of a
20 kDa peptidoglycan-associated lipoprotein, Pal (Karlsen et al. 2011 ). Immersion
of Atlantic salmon in vaccine preparations resulted in protection, even after 6
months (Holm and Jørgensen 1987 ). It has emerged that Ali. salmonicida vaccines
exert adjuvant activities on T-dependent and T-independent antigens in salmonids,
namely rainbow trout. Essentially, vaccine preparations enhance antibody responses
notably to LPS (Steine et al. 2001 ). Thus, the inclusion of inactivated Ali. salmonicida antigens in vaccines preparations may have an overall benefi cial effect on the
recipient fi sh (Hoel et al. 1998 ). The incubation temperature used to culture Ali.
salmonicida is an important aspect of vaccine production with 10 °C (this coincides
with the upper range of water temperatures at which coldwater vibriosis is most
likely to occur) rather than 15 °C giving a higher yield of cells in broth media
(Colquhoun et al. 2002 ).
At least one vaccine has been commercialised in a polyvalent form.
Immunostimulants/Dietary Supplements Synergism between low levels of iron
and high amounts of long-chain polyunsaturated fatty acids led to and RPS 96 %
after challenge with Ali. salmonicida (Rørvik et al. 2003 ). Carvacrol, which in part
of the essential oil of plants including oregano ( Origanum vulgare ) was fed at
Aliivibrio salmonicida