634
played haemorrhagic areas in the jaw, cranium and at the base of the fi ns. Control
may be possible by means of antibiotic therapy as the pathogen was susceptible to
amoxicillin and penicillin G, but resistant to cotrimoxazole and oxytetracycline
(Palmer et al. 1994 ).
Another unidentifi ed Gram-negative organism was linked to a previously undescribed condition, coined Varracalbmi (= bloody eye), in Norwegian farmed
Atlantic salmon. The disease, which occurred in northern Norway during 1989–
1992, was described as a haemorrhagic, necrotizing, pyogranulomatous infl ammation of the eye, being termed panophthalmitis. Lethargy, deep ulcers, necrosis, and
haemorrhagic, granulomatous, pyogenic visceral organs occurred (Valheim et al.
2000 ). Mortalities of only 2.5 % were reported (Valheim et al. 2000 ). The source of
the infection was unknown, but may well have been another cold water marine fi sh
(Valheim et al. 2000 ). The unnamed organism associated with Varracalbmi grew at
22 °C on 5 % (v/v) citrated bovine blood agar supplemented with 2 % (w/v) NaCl
from inocula obtained from dermal lesions, kidney and liver (Valheim et al. 2000 ).
The organism was challenged i.p. into groups of Atlantic salmon smolts (average
weight = ~37 g) with the outcome that total mortality resulted with a dose of 4 × 10
7
cells (51 % mortality with a dose of 4 × 10
4 cells) (Valheim et al. 2000 ).
The authors considered that the organism is linked to the Pasteurellaceae or
Vibrionaceae (Valheim et al. 2000 ), and this seems appropriate.
An unusual Gram-negative bacterial culture was linked to ulceration (singular
circular ulcers of 10–15 mm in diameter on the fl ank) in Scottish farmed rainbow
trout (Fig. 11.3 ) (Austin et al . 2003a ). The unnamed organism was linked to
Ultramicrobacterium by 16S rRNA sequencing (homology = 95 %) (Austin et al.
2003a ).
Gram-negative bacteria were associated with a mass mortality of cultured rockfi sh (Sebastes schlegeli) in Japan during the spring of 2001, with the disease signs
refl ecting aneurysms, hyperplasia, lamellar fusion, haemorrhaging and necrosis of
Box 11.16: Causal Agent of Varracalbmi
The small, i.e. 1 mm in diameter, colonies, which grow anaerobically into the
agar medium, comprise Gram-negative non-motile slender fermentative rods
sometimes arranged as short chains (when grown in broth), which produce
arginine dihydrolase, oxidase but not catalase, indole or lysine or ornithine
decarboxylase, attack starch (weakly) and lecithin (weakly) but not aesculin,
casein, chitin, gelatin, Tween 20 or 80 or urea, and are non-haemolytic
(α-haemolysis is recorded after a week), require NaCl, and grow at 4–22 °C,
do not reduce nitrates, but are sensitive to the vibriostatic agent, O/129.
Growth occurs with galactose, glucose, glycerol, lactose, maltose, mannitol,
mannose and sorbitol, but not arabinose, cellobiose, erythritol, melibiose, raffi nose or rhamnose (Valheim et al. 2000 ).
11 Miscellaneous Pathogens
played haemorrhagic areas in the jaw, cranium and at the base of the fi ns. Control
may be possible by means of antibiotic therapy as the pathogen was susceptible to
amoxicillin and penicillin G, but resistant to cotrimoxazole and oxytetracycline
(Palmer et al. 1994 ).
Another unidentifi ed Gram-negative organism was linked to a previously undescribed condition, coined Varracalbmi (= bloody eye), in Norwegian farmed
Atlantic salmon. The disease, which occurred in northern Norway during 1989–
1992, was described as a haemorrhagic, necrotizing, pyogranulomatous infl ammation of the eye, being termed panophthalmitis. Lethargy, deep ulcers, necrosis, and
haemorrhagic, granulomatous, pyogenic visceral organs occurred (Valheim et al.
2000 ). Mortalities of only 2.5 % were reported (Valheim et al. 2000 ). The source of
the infection was unknown, but may well have been another cold water marine fi sh
(Valheim et al. 2000 ). The unnamed organism associated with Varracalbmi grew at
22 °C on 5 % (v/v) citrated bovine blood agar supplemented with 2 % (w/v) NaCl
from inocula obtained from dermal lesions, kidney and liver (Valheim et al. 2000 ).
The organism was challenged i.p. into groups of Atlantic salmon smolts (average
weight = ~37 g) with the outcome that total mortality resulted with a dose of 4 × 10
7
cells (51 % mortality with a dose of 4 × 10
4 cells) (Valheim et al. 2000 ).
The authors considered that the organism is linked to the Pasteurellaceae or
Vibrionaceae (Valheim et al. 2000 ), and this seems appropriate.
An unusual Gram-negative bacterial culture was linked to ulceration (singular
circular ulcers of 10–15 mm in diameter on the fl ank) in Scottish farmed rainbow
trout (Fig. 11.3 ) (Austin et al . 2003a ). The unnamed organism was linked to
Ultramicrobacterium by 16S rRNA sequencing (homology = 95 %) (Austin et al.
2003a ).
Gram-negative bacteria were associated with a mass mortality of cultured rockfi sh (Sebastes schlegeli) in Japan during the spring of 2001, with the disease signs
refl ecting aneurysms, hyperplasia, lamellar fusion, haemorrhaging and necrosis of
Box 11.16: Causal Agent of Varracalbmi
The small, i.e. 1 mm in diameter, colonies, which grow anaerobically into the
agar medium, comprise Gram-negative non-motile slender fermentative rods
sometimes arranged as short chains (when grown in broth), which produce
arginine dihydrolase, oxidase but not catalase, indole or lysine or ornithine
decarboxylase, attack starch (weakly) and lecithin (weakly) but not aesculin,
casein, chitin, gelatin, Tween 20 or 80 or urea, and are non-haemolytic
(α-haemolysis is recorded after a week), require NaCl, and grow at 4–22 °C,
do not reduce nitrates, but are sensitive to the vibriostatic agent, O/129.
Growth occurs with galactose, glucose, glycerol, lactose, maltose, mannitol,
mannose and sorbitol, but not arabinose, cellobiose, erythritol, melibiose, raffi nose or rhamnose (Valheim et al. 2000 ).
11 Miscellaneous Pathogens