Pasteurellosis

Physical Signs:

• Septicemia: Systemic bacterial infection affecting multiple organs 12.
• Hemorrhages: Reddened areas on internal organs 3.
• Exophthalmia: Bulging or protruding eyes may occur in some cases 3.

Behavioral Changes:

• Lethargy: Reduced activity and sluggish swimming 2.
• Loss of Appetite: Decreased feeding behavior 2.
• Abnormal Swimming Patterns: Fish may swim sluggishly and in random patterns 2.

Early Stages: Subtle signs such as reduced feed intake and slight lethargy.

Advanced Stages: More pronounced physical symptoms such as septicemia and increased mortality 12.

Impact on Fish Health: Pasteurellosis severely compromises overall health and can lead to significant mortality if left untreated 12.

Causative Agent: Various Pasteurella species, including Pasteurella skyensis and other related bacteria of the Pasteurellaceae family 125.

Transmission Methods:

• Waterborne: The bacterium can spread through water, especially under conditions of poor water quality 2.
• Potential transmission between species: Concerns about transmission between lumpsucker and Atlantic salmon in aquaculture settings 14.

Environmental Factors: Stress conditions, such as delousing treatments, can increase susceptibility to Pasteurellosis 2.

Farm Management Practices: Use of cleaner fish (e.g., lumpsucker) for delousing may contribute to the spread of the disease 14.

Clinical Examination: Observation of physical and behavioral symptoms 2.

Laboratory Tests:

• Bacterial Culture: Isolation and identification of Pasteurella species from tissue samples 2.
• MALDI-TOF MS: Mass spectrometry for rapid identification of bacterial species 2.
• Whole Genome Sequencing: For precise identification and discrimination of Pasteurella strains 25.

• Antibiotics: Administered through feed, but may have limited efficacy due to reduced appetite in affected fish 2.
• Alternative Methods: Injection of antibiotics may be considered for smaller populations or valuable fish 2.

Biosecurity Protocols:

• Implementing strict biosecurity measures to prevent the introduction and spread of Pasteurella species 2.
• Regular monitoring and rapid diagnosis of suspected cases 2.

Farm Management Practices:

• Careful consideration of cleaner fish use and potential disease transmission 14.
• Proper cleaning and disinfection of equipment between treatments 2.

Notable Outbreaks:

• Norway (2020-2022): Approximately 50 diagnosed cases annually in south-western Norway 5.
• Scotland: Outbreaks associated with Pasteurella skyensis serotype O2 2.

Response Strategies and Outcomes:

• Norway: Increased focus on rapid diagnosis and identification of Pasteurella strains 25.
• Scotland: Development of serotyping methods for _P. skyensis 2.

Lessons Learned: The importance of routine bacteriology, rapid diagnosis, and proper biosecurity measures in controlling Pasteurellosis outbreaks 25.

Pasteurellosis Incidence in Norway:

• Pasteurellosis was first diagnosed in Atlantic salmon in Norway in 1989 2.
• It has been a rapidly increasing problem in Atlantic salmon in Western Norway over the last three years 2.
• Approximately 50 diagnosed cases were registered annually in farms in south-western Norway from 2020 to 2022 7.

Geographical Spread:

• Recent outbreaks have been primarily associated with Western Norway 27.

Economic Impact:

• While specific economic figures are not provided, the increasing frequency of outbreaks suggests a growing economic concern for the salmon farming industry in Norway 27.

Treatment & Management:

• There is currently no commercially available vaccine against pasteurellosis in lumpsucker or salmon 4.
• Research is ongoing to establish factors leading to disease outbreaks and how to best experimentally challenge fish with this emerging pathogen 4.

Pasteurellosis Incidence in Scotland:

• Pasteurella skyensis was first discovered in Scotland at three separate sites over a four-year period 2.
• Recent outbreaks in Scotland have been associated with serotype O2 of P. skyensis 2.

Geographical Spread:

• Specific geographical information for Scotland is not provided in the search results.

Economic Impact:

• Specific economic impact data for Scotland is not mentioned in the search results.

Treatment & Management:

• Similar to Norway, there is no mention of a commercially available vaccine for pasteurellosis in Scotland 4.