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