Why do we need to sample?
Disease outbreaks and fish kills
What is the OiE
World organisation for animal health
Where is the OiE located
Paris
What are most of the current OIE-listed fish diseases
Viral
What is AQUAVETPLAN stand for
The Australian Aquatic Veterinary Emergency Plan
What is. AQUAVETPLAN
A series of manuals that outline Australia’s approach to national disease preparedness and proposes the technical response and control strategies to be activated in a national aquatic animal disease emergency
What is the most intel test for diagnosis
Histopathy
What does the presence of bacterial infection not exclude
Viruses
What can both bacterial and fungal infections cause
Erosion which can be problematic because of contamination of samples from organisms in the environment
What type of fish should be submitted where possible for diagnosis
Live fish
Where live fish aren’t possible what fish should be used
Euthanised and either cooled and dispatched on ice (NOT frozen) or samples cultured or fixed before dispatch
What is the problem wish fish after death
Fish body temp alters to the conditions they are in, so after death their enzymes are still active causing rapid autolysis
When toxins are expected what should be submitted
Live fish for general examination and exclusion but water sample should be included
What are frozen fish useful for
Tocicological analysis and gross pathology
What are fixes preserved specimens suitable for
Gross and histological examination including immunohistochemical staining but not for the isolation of pathogens
When affected live fish or fish that are chilled very soon after death cannot reach the lab in suitable times what should be done
Samples for specific tests should be selected prior to dispatch
Samples for bacterial culture should be inoculated directly onto culture, why is this and what should be done if this is not possible
Transport media may not support fish pathogens
Tissue from culture should be separated from non-sterile tissues such as the gut and skin
If delays in virus culture are unavoidable what should be done
Samples for diagnostic virology can be held frozen at -20 degrees Celsius or below
When taking history what should be asked
- Affected fish populations
- The cohorts
- The environment
What to ask in the history of farmed fish
- Type of containment and time since establishment
- Recent introduction or alterations or failures of water filtration or supply
- Water and environmental data
- Management data
- Details of specimens submitted and analyses requested
What should submissions for disease diagnosis from farmed fish
- Submitter’s and owner’s name and address
- Affected population data
- Data on the disease
When wild fish die what should be submitted
Fish samples and a variety of water samples
What to submit the there is a wild fish kill of unknown cause
- Estimated number fo affected and distressed fish
- Type of species involved
- Size range of affected fish
- The area covered
- Range of decomposition
- Behaviour of distressed fish
- Other aquatic animals affected?
- Water data should be include a description of the type of waterway
- Environmental data should include a description of the land use in the area, and the presence of any effluent or discharge
- Weather conditions should be described
Water samples are needed more often than equivalent environmental samples relating to mammals because
- Limitations on oxygen concentrations in water and the factors that can further reduce this
- Increased dependence of poikilotherms on environmental stability
- The mixture of food, fish and pollutant waste in the fish’s respiratory environment
