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17 Cards in this Set
- Front
- Back
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Why do we study fish disease |
1. Fish supply is running out 2. 80% of world fish are gone 3. Large predatory fish population has dropped by 90% 4. Average size of large "trophy" fish has decreased by over 50% 5. Predicted that world wide fisheries collapse by 2048 or sooner |
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Aquaculture success? |
1/3 of all farmed fish/shrimp never reach marketable size |
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Conditions affecting fish Health |
1. species hardiness 2. Age 3. Husbandry practices- handling, facilities, living conditions, packing density 4. Environment- temp, water quality, O2, pH, etc 5. Nutrition 6. Pathogens |
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Stress and Fish Disease |
Stress is a major player in maintaining captive fish health - stressors= high packing density, handleing, poor water quality, temp changes -Stress--> Hypothalamic, pituitary, adrenal axis --> cortisol--> immune suppression
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signs of stress |
-increased respiration - increased mucous production - dark pigmentation |
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Results of stress |
1. infection via opportunistic pathogen 2. death |
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Furunculosis |
-Bacterial disease -Aeromonas salmonicida virulence factors: A-layer protein, ECP Extracellular products (toxins, proteases) -subcutaneous hemorrhagic lesions (furucles) -time until death depends on water temp -Diagnosis via ELISA and PCR -Treatment: antibiotics and vaccines (oil adjuvant) |
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Enteric red-mouth disease |
-Bacterial Disease -Yersinia ruckeri -hemorrhage of the operculum and mouth -internal hemorrhage and splenomegally -virulence associated w/ unknown plasmid -Treatment: antibiotics and vaccine -antibiotics are less common now -no cell immunity with vaccines
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Columnaris disease |
-Bacterial -Flexibacter columnaris -old disease that is re-emerging - causes effacing, erosive lesions of the skin -bacteria can consume the skin w/in days -Treatment:antibiotics (no vaccines) -Only classical pathway of compliment works with this disease- needs antibodies
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Enteric Septicemia of Catfish |
-Bacterial -Edwarsiella ictaluri -Main disease of concern in farmed catfish -causes necrosis of spleen and liver -characteristic nasal ulcer -flagallated bacteria -seasonal disease when water is 28-29 degrees (May and October) -bath vaccines available 50-60% protection |
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Bacterial Kidney Disease |
-Bacterial -Renibacterium salmonimarum -early gross signs = pantropic hemorrhage -large granulomatous lesions withing the kidney and spleen - Bacteria induces hemolytic, proteolytic, exotoxin, catalase and DNAse activities -P57 is a major virulenc factor- intracelluar invasion of leukocytes and immunosuppression -no vaccine
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Vibriosis |
-Bacteria -Vibriosis anguilarum and Vibrio salmonicida -causes severe multifocal to coalesing hemorrhage and ulcuration -occurs during rapid water changes --> stress -V. anguilarum secretes lethal ECP's --> agglutination of RBC -vaccines available |
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Infectious hematopoietic necrosis virus |
-causes widespread dermal haemorrhage -affects young fish especially -can kill a fish in 2 days -spinal deformities -characteristic thick trailing fecal casts -mostly effects salmonids -no commercial vaccines -DNA vaccine available in Canada -both vertical and horazontal transmission |
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Viral Hemorrhagic Septicaemia Virus |
-RNA virus related to IHNV -related to rabies virus -widespread hemorrhage and rapid death -exopthalmia -causes marked kidney necrosis --> loss of hematopoietic cells kidney is site of hematopoiesis in fish -DNA vaccine available but not in US |
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Koi Herpesvirus (KHV) |
-important disease of asian countries over last 10 years -affects wild and ornamental carp -lethargy, erratic swimming, increased mucous production, hepatic hemorrhage, gill necrosis -highly contagious - 90% of koi in thailand have this disease -Diagnosis via cell tissue culture and PCR |
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Oomyctes (water molds) |
most common fish fungal diseases - Saprolegnia is the most common -can consume 1/3 of the fishes body and the fish will still swim -very common in asian markets due to warm climates -generally an opportunistic/secondary infection -induce lymphocytopenia and impairment of hematopoietic organs -No vaccines |
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treatment of fungal diseases |
-he suggests malachite green- what a joke known carcinogen, completely illegal to use in food fish, not even used in ornamentals any more totally outdated medicine |
