This study was conducted to determine the effects of a co-infection with Moritella viscosa at different exposure levels of sea lice Lepeophtheirus salmonis in Atlantic salmon (Salmo salar). M. viscosa (1.14 × 106 cfu/ml) was introduced to all experimental tanks at 10 days post-lice infection (dpLs). Mean lice counts decreased over time in both the medium lice co-infection (31.5 ± 19.0 at 7 dpLs; 16.9 ± 9.3 at 46 dpLs) and high lice co-infection (62.0 ± 10.8 at 7 dpLs; 37.6 ± 11.3 at 46 dpLs). There were significantly higher mortalities and more severe skin lesions in the high lice co-infected group compared to medium lice co-infected group or M. viscosa-only infection. Quantitative gene expression analysis detected a significant upregulation of genes in skin from the high lice co-infection group consistent with severe inflammation (il-8, mmp-9, hep, saa). Skin lesions retrieved throughout the study were positive for M. viscosa growth, but these were rarely located in regions associated with lice. These results suggest that while M. viscosa infection itself may induce skin lesion development in salmon, co-infection with high numbers of lice can enhance this impact and significantly reduce the ability of these lesions to resolve, resulting in increased mortality.

中文翻译：

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鲑鱼Leopophtheirus和粘稠莫氏菌共感染对大西洋鲑鱼（Salmo salar）的炎症和免疫反应的影响。

进行这项研究是为了确定在大西洋鲑鱼（Salmo salar）中海虱Lepeophtheirus鲑鱼的不同暴露水平下，粘稠莫氏杆菌共同感染的影响。在虱子感染（dpLs）后第10天，将粘稠支原体（1.14×106 cfu / ml）引入所有实验池。中虱共感染（7 dpLs时为31.5±19.0; 46 dpLs时为16.9±9.3）和高虱子共感染（7 dpLs时为62.0±10.8; 46 dpLs时为37.6±11.3）均会导致平均虱子计数随时间下降。与中等虱子共同感染组或仅粘液支原体感染相比，高虱子共同感染组的死亡率和皮肤损伤更为严重。定量基因表达分析检测到高虱子共感染组皮肤中的基因显着上调，与严重发炎相一致（il-8，mmp-9，hep，saa）。整个研究中发现的皮肤病变对粘膜分枝杆菌生长呈阳性，但很少位于与虱子相关的区域。这些结果表明，粘膜分枝杆菌感染本身可能会导致鲑鱼皮肤病变的发展，但同时感染大量虱子会增强这种影响，并显着降低这些病变的解决能力，从而导致死亡率增加。