Download VIRUS DISEASES

FISH VIRAL DISEASES
• VIRUS MUST HAVE HOST TO
SURVIVE AND REPLICATE
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VIRION
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• SOME HAVE ADDITIONAL LIPID
GLYCOPROTEIN COAT
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Size of particles
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VIRUS TYPES
• DNA
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HERPESVIRUS, IRIDOVIRUSES
• RNA
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• RABDOVORUSES, RETROVORUSES
Effects of Virus Infection
• Histological changes
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• CPE •
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Host Response/Outcome
• No clinical disease
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• Clinical disease
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MANAGEMENT OPTIONS
FOR VIRUSES
• AVOID
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• VACCINATE
• REDUCE RISKS
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DNA viruses -Herpes group
• Channel catfish virus (CCV)
• Oncorhynchus masou virus (OMV)
• Walleye herpesvirus (WHV)
DNA - Iridovirus
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Lymphocystis Disease - LDV
Atlantic Cod Iridovirus
Viral Erythrocytic Necrosis -VEN
White Sturgeon Iridovirus
Viral Erythrocyte Inclusion Body
Syndrome - EIBS
Channel catfish virus
• Acute disease
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• Clinical signs
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• Diagnosis
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Erythrocytic Inclusions
• VEN
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• No Red Blood Cells
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• Diagnosis
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EIBS
• First detected spring Chinook salmon
LWS hatchery 1982. Hematocrits 2 50%
RNA viruses Rhabdoviruses
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• IHNV
– Infectious hematopoietic necrosis virus
• VHSV
– Viral Hemorrhage septicemia virus
IHNV
• Originated as three strains in Western North
American salmonids
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• Signs
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• Diagnosis
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Strains and Virulence
• Single stranded RNA genome that
encodes five structural proteins.
• Other factors affecting Virulence
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Attenuated Virus
• Nan Scott Lake and Hagerman strains
(multiple passages)
• Vaccines
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IHNV Control Methods
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VHSV- Viral Haemorrhagic
Septicemia Virus
• Described in RBT in Denmark 1949
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VHSV
• Signs
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• Diagnosis
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Marine Reservoir for Pacific
Northwest Isolates
• Herring Stocks affected severely
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Birnaviridae - IPNV
• Infectious Pancreatic Necrosis
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IPN
• Signs
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• Diagnosis
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IPNV
• Inactivated by chlorine and iodine
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DI - DEFECTIVE
INTERFERING PARTICLES
• GENOME DEFFECTIVE
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