Scrutinizing the triad of Vibrio tapetis, the skin barrier and pigmentation as determining factors in the development of skin ulcerations in wild common dab (Limanda limanda)

Abstract

Recently, Vibrio tapetis was isolated for the first time from skin ulcerations in wild-caught common dab ( Limanda limanda ). To further examine its role in the development of these skin lesions, an in vivo experiment was performed. The significance of the skin barrier and in addition the difference between pigmented and non-pigmented side were investigated. Hence, the skin of common dab was treated in three different ways on both the pigmented and non-pigmented side. On a first “treatment zone”, the scales and overlying epidermal tissue were removed whereas in a second zone only the mucus was discarded. The third zone served as a non-treated zone. Thereafter, fish were challenged with V. tapetis . The control group was sham treated. Mortality, clinical signs, severity and size of the developing lesions were recorded. All animals were sacrificed and sampled 21 days post-inoculation. Significantly more fish of the group challenged with V. tapetis died compared to the control group with the highest incidence occurring 4 days post-inoculation. Fish challenged with V. tapetis developed more severe skin ulcerations. In zones where scales and epidermal tissue were removed, the ulcerations were more severe compared to zones where only mucus was eliminated. Ulcerations occurred more frequently, were more severe and larger on the pigmented side. Our data represents prove of V. tapetis as causative agent of ulcerative skin lesions although prior damage of the skin seems to be a major contributing factor. Furthermore, the pigmented side seemed predisposed to the development of skin ulcerations. Electronic supplementary material The online version of this article (10.1186/s13567-019-0659-6) contains supplementary material, which is available to authorized users.

First report of lesions resembling red mark syndrome observed in wild‐caught common dab (Limanda limanda)

“…The fish (21–81 months) were part of an experimental challenge study whereby the pathogenesis of a Vibrio tapetis infection was investigated in common dab (Vercauteren et al, ). These fish were caught at sea and, after an acclimatization period of 18 days, stocked in five groups of 12 animals per experimental unit (1 × 1 × 0.5 m; 450 L).…”

“…tured freshwater rainbow trout. The present report describes abnormal changes in the skin in marine common dab(Limanda limanda) caught in the Belgian part of the North Sea having various common features with lesions associated with RMS.The fish (21-81 months) were part of an experimental challenge study whereby the pathogenesis of a Vibrio tapetis infection was investigated in common dab(Vercauteren et al, 2019). These fish were caught at sea and, after an acclimatization period of 18 days, stocked in five groups of 12 animals per experimental unit (1 × 1 × 0.5 m; 450 L).…”

Pinpointing the role of Aeromonas salmonicida in the development of skin ulcerations in common dab (Limanda limanda)

“…The skin of all fish was treated in three ‘treatment zones’ (each ± 2.3 cm 2 , 0.5 cm interspace) on both pigmented (P) and non‐pigmented (NP) sides (Vercauteren et al, ). One zone was mechanically treated (MT) whereby the scales and overlying epidermis were removed by scraping with a scalpel.…”

“…The third zone served as a non‐treatment zone (NT) where skin was left intact. The sequence of all treatments was altered on each fish, resulting in six subgroups (1–6) of 10 fish each: (subgroup 1) MT–CT–NT; (subgroup 2) MT–NT–CT; (subgroup 3) NT–MT–CT; (subgroup 4) NT–CT–MT; (subgroup 5) CT–NT–MT; and (subgroup 6) CT–MT–NT (Vercauteren et al, ).…”

“…Disruption of the mechanical, chemical and immunological barrier formed by the skin and mucus, caused by abrasion or pollution, may increase the susceptibility to bacterial infection and subsequent skin ulceration development. Indeed, it has been previously demonstrated that Vibrio tapetis can cause ulceration of damaged skin in common dab ( Limanda limanda ) with the pigmented side being seemingly predisposed (Vercauteren et al, ).…”