514
Characteristics of the Pathogen
Fifteen Icelandic and one Norwegian isolates were recovered and equated with V.
logei (Benediktsdóttir et al. 1998 ). Then, the species was transferred to a newly created genus Aliivibrio as A. logei on the basis of phylogeny principally involving
sequencing of the 16S rRNA gene (Urbanczyk et al. 2007 ).
Epizootiology
It may be assumed that the source of the bacteria was seawater, although Ali. logei
has been recovered from the digestive tract of larval cod (Reid et al. 2009 ).
Aliivibrio salmonicida
Characteristics of the Disease
With the tremendous increases in production of Atlantic salmon in Norway, it was
perhaps inevitable that at some time a new or emerging disease would cause havoc
to the industry. Then in 1979, such a “new” disease appeared in salmon farms
located around the island of Hitra, south of Trondheim in Norway. In 1983, the
disease appeared in Stavanger and, in particular, the large number of fi sh farms in
the Bergen region. The disease, coined coldwater vibriosis or Hitra disease (Egidius
et al. 1981 ), occurs mainly during the period of late autumn to early spring. The
disease is now widespread throughout Norway, and there are some reports of outbreaks in Scotland, Shetland (Bruno et al. 1985 ) and Canada. The disease resembles
a generalised haemorrhagic septicaemia. Externally, haemorrhaging may be evident
around the abdomen (Holm et al. 1985 ). Internally, there is often evidence of anaemia, haemorrhaging on the organs, swim bladder and abdominal wall and posterior
gastro-intestinal tract (Poppe et al. 1985 ; Holm et al. 1985 ; Egidius et al. 1986 ).
Microscopy suggests that bacteria are rampant throughout infected fi sh, and especially in the blood and kidney of moribund and freshly dead specimens.
Box 10.3: Aliivibrio logei
Cultures do not produce arginine dihydrolase, indole or lysine or ornithine
decarboxylase. Blood (haemolysis) and chitin are degraded, but not starch.
Acid is produced from N-acetyl glucosamine, glycerol, maltose, mannose,
ribose, sucrose and trehalose.
10 Vibrios
Characteristics of the Pathogen
Fifteen Icelandic and one Norwegian isolates were recovered and equated with V.
logei (Benediktsdóttir et al. 1998 ). Then, the species was transferred to a newly created genus Aliivibrio as A. logei on the basis of phylogeny principally involving
sequencing of the 16S rRNA gene (Urbanczyk et al. 2007 ).
Epizootiology
It may be assumed that the source of the bacteria was seawater, although Ali. logei
has been recovered from the digestive tract of larval cod (Reid et al. 2009 ).
Aliivibrio salmonicida
Characteristics of the Disease
With the tremendous increases in production of Atlantic salmon in Norway, it was
perhaps inevitable that at some time a new or emerging disease would cause havoc
to the industry. Then in 1979, such a “new” disease appeared in salmon farms
located around the island of Hitra, south of Trondheim in Norway. In 1983, the
disease appeared in Stavanger and, in particular, the large number of fi sh farms in
the Bergen region. The disease, coined coldwater vibriosis or Hitra disease (Egidius
et al. 1981 ), occurs mainly during the period of late autumn to early spring. The
disease is now widespread throughout Norway, and there are some reports of outbreaks in Scotland, Shetland (Bruno et al. 1985 ) and Canada. The disease resembles
a generalised haemorrhagic septicaemia. Externally, haemorrhaging may be evident
around the abdomen (Holm et al. 1985 ). Internally, there is often evidence of anaemia, haemorrhaging on the organs, swim bladder and abdominal wall and posterior
gastro-intestinal tract (Poppe et al. 1985 ; Holm et al. 1985 ; Egidius et al. 1986 ).
Microscopy suggests that bacteria are rampant throughout infected fi sh, and especially in the blood and kidney of moribund and freshly dead specimens.
Box 10.3: Aliivibrio logei
Cultures do not produce arginine dihydrolase, indole or lysine or ornithine
decarboxylase. Blood (haemolysis) and chitin are degraded, but not starch.
Acid is produced from N-acetyl glucosamine, glycerol, maltose, mannose,
ribose, sucrose and trehalose.
10 Vibrios