Winter ulcers of the skin in Atlantic salmon, <i>Salmo salar</i> L.: pathogenesis and possible aetiology

Salte, Ragnar; Rørvik, Kjell‐Arne; Reed, Erin M.; Norberg, Kari

doi:10.1111/j.1365-2761.1994.tb00265.x

Cited by 48 publications

(31 citation statements)

References 6 publications

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“…A recent study proposed that the typical lesions of winter ulcer resulted from thrombosed dermal vessels and the subsequent formation of subepidermal vesicles (Salte et al 1994). In the present study, small thrombi-like formations were also observed in small venules in the dermis, but only in the chronic stages of the disease.…”

Section: Discussionsupporting

confidence: 75%

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'Winter ulcer' in the Atlantic salmon Salmo salar. Pathological and bacteriological investigations and transmission experiments

Lunder¹,

Evensen²,

Holstad³

et al. 1995

Dis. Aquat. Org.

110

108

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ABSTRACT. The present study describes pathological changes and bacteriological findings in 'winter ulcer' in Atlantic salmon Salmo salar L. The transmissibility of the disease was also evaluated under experimental conditions. Skin changes were characterized by ulcers of varying size, and were categorized as acute to subacute, chronic, and regenerative/reparative. In the acute stages, lesions were superficial with scale loss and mild inflammation, while in the subacute stages ulcers were present that extended down to the underlying n~uscle. Histologically, the chronic stages were characterized by a severe inflammation of the dermis and of the interstitial muscle tissue. In the regeneration/reparation stages, a hyperplastic epidermis covered granulation tissue. Bacteriological investigations carried out in salmon sampled from 8 different farms with winter ulcer identified 2 groups of bacteria that were common in affected fish. The examinations performed in the present study indicate that both these groups belonged to the genus Vibrio, termed sp. 1 and sp. 2, respectively. Immunohistochemically, Vibrio sp. 1 and 2 were identified in situ associated with muscle tissue degeneration. Experimental infection with Vibno sp. 1 induced a disease similar to winter ulcer in Atlantic salmon, while inoculation with Vibrio sp. 2 had no effect. Cohabitation experiments showed that winter ulcer can be transmitted from diseased to healthy individuals, and that injection was not required to induce the process. However, mechanical skin lesions were a predisposing factor for ulcer formation. The present study provides evidence that winter ulcer is caused by an infection with a Vibrio-like bacterium, and that the disease can be transmitted through cohabitation and injection Pathological changes were not pathognomonic, and the severity of changes varied.

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Section: Discussionsupporting

confidence: 75%

“…The most recent study on winter ulcer proposed that the skin lesions develop as a result of vascular thrombosis of dermal vessels which produces vesicle formation, followed by mechanical disruption (Salte et al 1994). A further suggestion was that high levels of dietary iron could be a central factor.…”

Section: Inter-research 1995mentioning

confidence: 99%

'Winter ulcer' in the Atlantic salmon Salmo salar. Pathological and bacteriological investigations and transmission experiments

Lunder¹,

Evensen²,

Holstad³

et al. 1995

Dis. Aquat. Org.

110

108

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“…It should be noted that Moritella viscosa is also generally absent in early skin lesions with intact epidermis (data not shown) (Salte et al 1994). Likewise, in our field cases the long, slender rods were only seen in open lesions with lost epidermis and were never detected on or in the epidermis in the periphery of the ulcer.…”

Section: Discussionsupporting

confidence: 62%

Tenacibaculum sp. associated with winter ulcers in sea-reared Atlantic salmon Salmo salar

Olsen

Nilsen²,

Sandlund³

et al. 2011

Dis. Aquat. Org.

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Coldwater-associated ulcers, i.e. winter ulcers, in seawater-reared Atlantic salmon Salmo salar L. have been reported in Norway since the late 1980s, and Moritella viscosa has been established as an important factor in the pathogenesis of this condition. As routine histopathological examination of winter ulcer cases in our laboratory revealed frequent presence in ulcers of long, slender rods clearly different from M. viscosa, a closer study focusing on these bacteria was conducted. Field cases of winter ulcers during 2 sampling periods, 1996 and 2004-2005, were investigated and long, slender rods were observed by histopathological examination in 70 and 62.5% of the ulcers examined, respectively, whereas cultivation on marine agar resulted in the isolation of yellowpigmented colonies with long rods from 3 and 13% of the ulcers only. The isolates could be separated into 2 groups, both identified as belonging to the genus Tenacibaculum based on phenotypic characterization and 16S rRNA sequencing. Bath challenge for 7 h confirmed the ability of Group 1 bacterium to produce skin and cornea ulcers. In fish already suffering from M. viscosa-induced ulcers, co-infection with the Group 1 bacterium was established within 1 h. Ulcers from field cases of winter ulcers and from the transmission experiments tested positive by immunohistochemistry with polyclonal antiserum against the Group 1 bacterium but not the Group 2 bacterium. Our results strongly indicate the importance of the Group 1 bacterium in the pathogenesis of winter ulcers in Norway. The bacterium is difficult to isolate and is therefore likely to be underdiagnosed based on cultivation only. KEY WORDS: Winter ulcers · Tenacibaculum · Atlantic salmon · Transmission experiment · Moritella viscosa · Cod · Halibut Resale or republication not permitted without written consent of the publisherDis Aquat Org 94: [189][190][191][192][193][194][195][196][197][198][199] 2011 winter ulcers (Lunder et al. 1995, Benediktsdóttir et al. 1998; however, demonstration of pathogenicity for this bacterium under experimental conditions has so far been unsuccessful (Lunder et al. 1995). Many culture-based investigations of winter ulcers have resulted in the identification of mixed cultures of mainly Vibrio spp. (Benediktsdóttir et al. 1998, H. Nilsen & A. B. Olsen unpubl.).Worldwide, members of the Cytophaga-Flavobacterium-Bacterioides group are reported to cause mortality and economical losses because of skin ulcers and eroded fins of both freshwater and seawater fish species (Wakabayashi et al. 1986, Kent et al. 1988, Bernardet 1989, Bernardet & Kerouault 1989, Bernardet et al. 1990). The bacteria appear as yellow colonies with long, slender filamentous rods and are relatively difficult to culture. Four species are considered pathogenic to salmonids: Flavobacterium branchiophilum (bacterial gill disease in freshwater), F. columnare (freshwater above 14°C), F. psychrophilum (mainly rainbow trout in freshwater) and Tenacibaculum maritimum (prev. Flexibacter maritimus) in...

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“…Iron deficiency causes immune suppression, growth depression, changes in hematological parameters, susceptibility to diseases, poor food conversion and microcytic anemia in common carp (Tacon 1992;Andersen et al 1996;Kawatsu 1972;Sakamoto and Yone 1978). Iron is thus essential and in excess can be toxic (Salte et al 1994;Andersen et al 1997). Fish can absorb soluble iron from the water across the gill membrane and intestinal mucosa (Roedar and Roedar 1966;Sealey et al 1997).…”

Section: Introductionmentioning

confidence: 99%

Nano-Fe as feed additive improves the hematological and immunological parameters of fish, Labeo rohita H.

et al. 2013

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An experiment was conducted to compare the effects of iron oxide nanoparticles (T 1 ) and ferrous sulfate (T 2 ) on Indian major carp, Labeo rohita H. There were significant differences (P \ 0.05) in the final weight of T 1 and T 2 compared with the control. Survival rates were not affected by the dietary treatments. Fish fed a basal diet (control) showed lower (P \ 0.05) iron content in muscle compared to T 1 and T 2 . Furthermore, the highest value (P \ 0.05) of iron content was observed in T 1 . In addition, RBCs and hemoglobin levels were significantly higher in T 1 as compared to other treated groups. Different innate immune parameters such as respiratory burst activity, bactericidal activity and myeloperoxidase activity were higher in nano-Fe-treated diet (T 1 ) as compared to other iron source (T 2 ) and control in 30 days post-feeding. Moreover, nano-Fe appeared to be more effective (P \ 0.05) than ferrous sulfate in increasing muscle iron and hemoglobin contents. Dietary administration of nanoFe did not cause any oxidative damage, but improved antioxidant enzymatic activities (SOD and GSH level) irrespective of different iron sources in the basal diet.

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Winter ulcers of the skin in Atlantic salmon, Salmo salar L.: pathogenesis and possible aetiology

Cited by 48 publications

References 6 publications

'Winter ulcer' in the Atlantic salmon Salmo salar. Pathological and bacteriological investigations and transmission experiments

'Winter ulcer' in the Atlantic salmon Salmo salar. Pathological and bacteriological investigations and transmission experiments

Tenacibaculum sp. associated with winter ulcers in sea-reared Atlantic salmon Salmo salar

Nano-Fe as feed additive improves the hematological and immunological parameters of fish, Labeo rohita H.

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