FISH VIRAL DISEASES

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FISH VIRAL DISEASES

• VIRUS MUST HAVE HOST TO SURVIVE AND REPLICATE

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VIRION

• SOME HAVE ADDITIONAL LIPID GLYCOPROTEIN COAT

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Size of particles

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VIRUS TYPES

• DNA
• HERPESVIRUS, IRIDOVIRUSES
• RNA
• RABDOVORUSES, RETROVORUSES

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Effects of Virus Infection

• Histological changes
• CPE -

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Host Response/Outcome

• No clinical disease
• Clinical disease

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MANAGEMENT OPTIONS FOR VIRUSES

• AVOID
• VACCINATE
• REDUCE RISKS

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DNA viruses -Herpes group

• Channel catfish virus (CCV)
• Oncorhynchus masou virus (OMV)
• Walleye herpesvirus (WHV)

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DNA - Iridovirus

• Lymphocystis Disease - LDV
• Atlantic Cod Iridovirus
• Viral Erythrocytic Necrosis -VEN
• White Sturgeon Iridovirus
• Viral Erythrocyte Inclusion BodySyndrome - EIBS
  

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Channel catfish virus

• Acute disease
• Clinical signs
• Diagnosis

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Erythrocytic Inclusions

• VEN
• No Red Blood Cells
• Diagnosis

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EIBS

• First detected spring Chinook salmon LWS hatchery
  1982. Hematocrits 2 - 50

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RNA viruses Rhabdoviruses

• IHNV
• Infectious hematopoietic necrosis virus
• VHSV
• Viral Hemorrhage septicemia virus

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IHNV

• Originated as three strains in Western North
  American salmonids
• Signs
• 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
• 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
• Diagnosis

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IPNV

• Inactivated by chlorine and iodine

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DI - DEFECTIVE INTERFERING PARTICLES

• GENOME DEFFECTIVE