Viral Disease

1

• Viral Disease
• 1. Affect cultured species population
• 2. Tumor make harvestable-size unacceptable
• Effect of pollution on fish
• 1. Causing degradation of environment
• 2. Fish population can be measured by annual
  sampling
• 3. Fish served as biological indicators
  degradation
• Viral disease of salmonids
• 1. Infectious pancreatic necrosis virus (IPNV)
• Generally pathogen of freshwater fish
• 16 species of salmonid was serve as host

2

• Infected fish, dark, bilatheral exopthalmic,
  distended
• abdomen, pale to pink gill, erratic swimming.
  Internall,
• clear yellow fluid, gut is pale n void.
  Surived fish
• became carrier virus.
• 2. Viral hemorrhagic septicemia (VHS)
• Infect juvenile, subadults, adult, survived
  fish-carriers
• Reservoir, carrier fish, diseased fish,
  fish-eating birds
• Infected, dont feed, lethargic, hyperactive,
  darker,
• exopthalimic, gill pale, petechial hemorrhage.
  Internal,
• lesion, spleen enlarged n red.
• 3. Infectious hematopoietic necrosis (IHN)
• Acute, systemic disease caused by rhabdovirus
  in
• young cultuted trout n salmon in USA

3

• Severe in fry n fingerling losses 100, occur
  in 12
• 15ºC. Infected, lethargic swimming,
  exophthalmic,
• darker, abdominal swelling, pale gill,
  petechiae, spinal
• deformities.
• 4. Erythrocytic inclusion body syndrome (EIBS)
• Pasific salmon anemia virus, severe for
  juvenile coho
• n chinook salmon. Cytoplasmic inclusion in
• erythrocyte, hematocrit drop to 25 (lowest
  point),
• horizontal cohabitation, gill pale.
• Herpesvirus salmonis disease
• Infect rainbow trout n steelhead trout.
  Etiologival,
• Herpesvirus salmonis occur at 10ºC or less,
  dark
• pigmentation, stop eating after 2 week,
  lethargic,

4

• lay in bottom, exophthalmic, hemorrhage in
  eyes, gill
• pale, abdomen distended
• Oncorhynchus Masou Virus (OMV)
• Occur in young member genus Oncorhynchus,lethal
  in
• young fish, neoplastic in older. OMV is
  intriguing
• disease, lethal for 50-150 days lose appetite,
• exophthalmic, petechiae, liver white, spleen
  swollen.
• Neoplasm, 4 month after exposure n persit 1
  year,
• tumor in mouth, fin, gill cover, body surface,
  cornea of
• eyes, rarely in kidney.
• Transmission, vertical-reproductive products,
• horizontal via water.
• Chum salmon Reovirus (CSR)

5

• member fam Reoviridae, is not pathogenic.
• Viral disease of non-salmonid fishes
• Many produced tumor, papillomas, other type of
  growth
• skin n fin.
• 1. Erythrocytic necrosis virus (ENV)
• Viremic in reptile, amphibians n fishes -
  cytoplasmic
• inclusion bodies. Clin sign, anemia, pale gill
  n viscera,
• hematocrit low as 2-10.
• VEN increased susceptible to vibriosis n oxygen
  dep.
• 2. Lymphocystis
• Hypertrophic disease of cell in skin n fin.
  Affectd all
• age, trans depend host species, virus, temp,
  prev

6

• at cold n warm weather. Trans increased by
  density,
• trauma during spawning, by netting/tagging.
• Manifest, prod hypertrophied cell in con tissue
  in body
• surface n fins. Causing the poor of aesthetic.
• 3. Atlantic menhaden spinning disease (AMSD)
• Abnormal swimming, hyperemia, hemorrhage in eye
  n
• ven, spleen n brain congested, intestine bloody
  fluid.
• 4. Atlantic cod ulcus syndrome
• Signs, 2-8 mm papules, progress to ulcers,
  prevalent
• in autum, increased by pollution organic from
  fruit n
• vetetable processing plant.
• 5. Hirame Rhabdovirus (HRV)
• Signs, pale gill, abdominal distension,
  ascites,
• hemorrhages in skin n skeletal muscle.

7

• internal, gonadal congestion n hemorrhage
  organ.
• Occurs in hirame (flounder) and ayu.