Fish Flashcards
Non-lethal testing you can do on fish
Mucous scrape
Gill smear (mucus only or biopsy – not ideal
Faecal sample
Blood sample (may be lethal in small fish) for haematology (manual), limited biochemistry, PCR for known pathogens (gill swabs)
Lethal testing you can do on fish
Post-mortem examination
Histopathology (take ALL organs)
Microscopy of gill filaments
PCR for known pathogens on specified organs
Bacteriology of internal organs eg kidney
Why is sampling dead fish for histopathology srongly discouraged and PM assessment (unless fish are very recently dead) may be of limited use in many cases
Fish tissues decompose faster than mammals
HPE interaction
Host
Pathogen
Environment
What disease is common in suboptimal environmental conditions or in the presence of parasites
Gill disease
Fish with large skin lesions likely to die of ____________?
Osmoregulatory failure
NOTIFIABLE DISEASES IN FISH
Epizootic Hematopoetic Necrosis (EHN)
Viral Haemorrhagic Septicaema
Infectious Salmon Anemia
Infectious Hematopoetic Necrosis
Koi herpes virus
Gyrodactylus
Bacterial kidney disease
Spring viraemia of carp
Epizootic haematopoietic necrosis virus affects what kind of fish
Rainbow trout & red-fin perch
First signs of EHN infected perch are…
large-scale mortalities of the population
Swollen spleen and kidney, along with petechial haemorrhaging seen internally
In rainbow trout, more chronic presentation
the most serious disease of rainbow trout in aquaculture
VIRAL HAEMORRHAGIC SEPTICAEMIA (VHS)
Disease Characterised by lethargy interspersed with periods of frenzied, abnormal activity.
INFECTIOUS HAEMATOPOIETIC NECROSIS
GYRODACTYLUS SALARIS
External parasite primarily affecting Atlantic salmon
Chronic disease affecting salmonid species caused by Renibacterium salmoninarum.
BACTERIAL KIDNEY DISEASE (BKD)
Rhabdovirus carpio.
Affects all varieties of carp and other coarse fish species.
SPRING VIRAEMIA OF CARP (SVC)
Disease of Scottish salmon causing- Skin damage, stress and general weakness
Sea lice
What is one of the biggest health challenges facing salmon industry in Scotland.
Poor gill health
Increasing incidence and apparent complexity of gill disorders and other emergent diseases.
Pathogens of interest causing gill disease
Neoparamoeba perurans (AGD)
AMOEBIC GILL DISEASE (AGD) SCORE CARD
0-5
0- No sign of infection and healthy red colour
3- Established thickened mucus patch or spot groupings up to 20% of gill area
5-Extensive lesions covering most of the gill surface (50%+
How Does Plankton Harm Fish?
How Does Plankton Harm Fish?
Reducing O2 content in water
Physical damage
Toxic damage
Supersaturation
Vectors for bacteria
Monitor gill health using
Monitor gill health using:
Environmental measurements
Gill appearance + scores (AGD)
Other fish/site observations
Mucus scrapes
Regular qPCR from gill swabs
Histopathology ahead of any handling events or if any other concerns
Pancreas Disease (PD) is a disease caused by infection with a virus
Salmon Alphavirus
Cardiomyopathy Syndrome (CMS) is a disease caused by infection with a virus
Piscine myocarditis virus
Heart and Skeletal Muscle Inflammation (HSMI) is a disease caused by infection with a virus
Piscine Reovirus
