The aetiological agent of Tenacibaculosis (or yellow mouth) Tenacibaculum spp. infect multiple fin fish species globally and is a major pathogen of sea bass (Dicentrarchus
labrax), sea bream ( Sparus aurata), turbot (Psetta maxima), and Atlantic salmon ( Salmo salar L.) aquaculture. In Atlantic salmon, the disease and associated mortalities occur both in smolts soon after transfer to sea, and in larger adults. While the disease exhibits variable pathological manifestations, yellow mouth lesions, fin erosion, and skin lesions are characteristic of the disease.
In Canada, the disease causes significant losses to the industry and is a priority issue with annual cost of outbreaks for one Canadian company cited as $1.6 million. Moreover, instances of outbreaks in other geographical regions, e.g. Chile, Norway, and Scotland have increased in recent years. At current, there is no commercially available vaccines for use in salmonids and a reliance on therapeutic use of antibiotics has led to a strong need for the industry to establish efficacious alternatives.
Multiple isolates of T. maritimum , T. finnmarkense , and T. dicentrarchi , and one potentially novel species of Tenacibaculum originating from Western Canada (BC) were utilised in these studies. Investigations focussed on understanding the virulence, and compound factors that influence virulence, of the different isolates and species. Furthermore, the clinical presentation of the isolates, and understanding how challenge methods can be manipulated for the testing of different technologies and treatments are explored.
Isolates, within and between, species of Tenacibaculum
have significantly different virulence and clinical presentations. Furthermore, it has been identified that while most environmental, and other compound factors, influence infection and disease outcomes some are unique. The development of these disease models is an important step in the development of technologies to mitigate its impacts on the culture of Atlantic salmon. However, Tenacibaculosis is a complex disease, and often is not exclusive to the presence/ infection of fish by a single species. Therefore, current developments are focussed on multiple species infection models for use in the industry.