Experimental Induction of Tenacibaculosis in Atlantic Salmon ( Salmo salar L.) Using Tenacibaculum maritimum , T. dicentrarchi , and T. finnmarkense

• Published in: Pathogens
• Main Authors: Joseph P. Nowlan, Scott R. Britney, John S. Lumsden, Spencer Russell
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2021
• Subjects: aquaculture; tenacibaculosis; mouthrot; bath-exposure; dysbiosis; histopathology; Medicine; R; Atlantic salmon; Salmo salar
• Online Access: https://doi.org/10.3390/pathogens10111439; https://doaj.org/article/03668a47f58d48098f1cc5bd8c56dbd5

There is a limited understanding of the pathogenesis of tenacibaculosis in Atlantic salmon ( Salmo salar L.) and there are few reproducible exposure models for comparison. Atlantic salmon were exposed via bath to Tenacibaculum maritimum , T. dicentrarchi , or T. finnmarkense, and were then grouped with naïve cohabitants. Mortalities had exaggerated clinical signs of mouthrot, a presentation of tenacibaculosis characterized by epidermal ulceration and yellow plaques, on the mouth and less frequently on other tissues. Histopathology showed tissue spongiosis, erosion, ulceration, and necrosis ranging from mild to marked, locally to regionally extensive with mats of intralesional bacteria on the rostrum, vomer, gill rakers, gill filaments, and body surface. Exposure to T. maritimum resulted in less than a 0.4 probability of survival for both exposed and cohabitants until Day 21. Exposures to T. dicentrarchi resulted in 0 and 0.55 (exposed), and 0.8 and 0.9 (cohabitant) probability of survival to Day 12 post-exposure, while T. finnmarkense had a 0.9 probability of survival to Day 12 for all groups. This experimental infection model will be useful to further investigate the pathogenesis of tenacibaculosis, its treatment, and immunity to Tenacibaculum species.