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Virology > CDV, HeV, NDV > Flashcards

CDV, HeV, NDV Flashcards

1
Q

What is the structure of Paramyxoviridae viruses?

A
  • (-)ssRNA
  • 15kb
  • enveloped (gp H & F)
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2
Q

What is the stability of Paramyxoviridae viruses?

A
  • Sensitive to disinfectants
  • relatively unstable outside the host
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3
Q

What are some of the Paramyxoviridae viruses?

A
  • Canine Distemper Virus (CDV)
  • Newcastle disease virus (NDV)
  • Hendra Virus (HeV)
  • Measles
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4
Q

What is Canine Distemper Virus (CDV)?

A
  • Highly contagious, systemic viral disease of dogs
  • Seen world wide
  • Large # of species susceptible:
    • Canidae
    • Mustelidae (ferret, mink, otter, badger)
    • Procyonidae (raccoon)
    • Viveridae (palm civet)
    • Ailuridae (red panda)
    • Ursidae
    • Felidae (large cats)
  • Domestic dogs are the reservoir species
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5
Q

How is CDV transmitted?

A
  • Primary route: aerosol droplets from infected animals
    • Virus shedding may occur for several months
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6
Q

What is Phase 1 of CDV infection?

A
  • Initial virus replication occurs in the lymphatic tissues of the respiratory tract
    • macrophages and bronchial ln
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7
Q

What is Phase 2 of CDV infection?

A
  • Within 1 week:
    • a cell-associated viremia results in virus replication spreading to all lymphatic tissues
      • Spleen, bone marrow, thymus, and lymphocytes
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8
Q

How does CDV cause immune suppression?

A
  • Depletion of vascular CD3+ T cells and CD21+ B cells within 3 days after infection
  • Monocyte apoptosis by 6 days post infection
  • Necrosis and depletion of the cortical region of the lymph nodes occurs
  • Leukopenia!
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9
Q

How does the body fight against CDV?

A
  • Both cell-mediated and humoral immune response necessary for protection
  • Degree of viremia and extent of viral spread is moderated by the level of specific humoral immunity (neutralizing Abs) during the viremic period
    • If neutralizing Abs are not present, virus persists in the lymphatic system and spreads
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10
Q

What is Phase 3 of CDV infection?

A
  • “mucosal phase”
  • Viral infection spreads to respiratory, gastrointestinal, and urogenital epithelium, skin, endocrine tissues, CNS and optic nerves
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11
Q

What is a pantropic virus?

A

virus with affinity for many tissues

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12
Q

What are the clinical signs of CDV?

A
  • Biphasic fever
  • Neurological signs
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13
Q

What is biphasic fever associated with CDV?

A
  • Transient fever ⇢ subclinical
    • May have leukopenia
    • may have inappetence
    • 3-6 dpi then subsides
  • Second fever ⇢ Clinical signs occur
    • Serous nasal discharge, rhinitis, mucopurulent ocular discharge, conjunctivitis, cough, dyspnea, diarrhea, vomiting, lethargy, dermatitis, and inappetence
    • Typically complicated by secondary bacterial infections
    • Thoracic radiographs may reveal interstitial pneumonia
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14
Q

What neurological signs are associated with CDV?

A
  • Longer courses of illness - onset may be delayed due to chronic progressive demyelination w/in CNS
  • Encephalomyelitis
    • may occur with other signs, follow systemic disease, or alone
    • Circling, blindness, head tilt, nystagmus, paresis to paralysis, focal to generalized seizures
    • Localized involuntary muscle twitching, convulsion characterized by salivation and chewing movements of the jaw
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15
Q

What is the pathogenesis of Acute CNS infections with CDV?

A
  • CDV targets Neurons and Glial cells ⇢ Neuronal degeneration and inflammation (grey matter disease)
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16
Q

What is the pathogenesis in Subacute CNS infections with CDV?

A
  • CDV targets oligodendrocytes ⇢ down-regulation of myelin production (white matter disease)
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17
Q

Which is more common grey or white matter disease with CDV infections?

A
  • typically mixed
  • pure grey matter disease is rare
18
Q

What is “Old dog encephalitis”

A
  • Chronic distemper encephalitis
  • Ataxia, head pressing, continual pacing, uncoordinated hypermetria
  • May be seen in fully vaccinated adult dogs w/out a history of acute CDV infections
  • CDV antigen detected in brain but not infectious virus
  • Neurological signs due to inflammatory reaction associated with persistent CDV infection in CNS
    • Poorly understood, mechanism unknown
19
Q

What are issues are seen post CDV infection?

A
  • Cutaneous hyperkeratosis
  • Enamel hypoplasia
20
Q

What is cutaneous hyperkeratosis associated with post CDV infection?

A
  • On the footpads and epithelium of nasal planum
    • Keratinocyte proliferation
    • Callusing of the nose and footpads
    • Hard pad disease
21
Q

What is enamel hypoplasia associated with post CDV infection?

A
  • infected puppies whose permanent teeth have not erupted
  • CDV targets the ameloblastic epithelium (makes tooth enamel)
  • Enamel defects (focal depressions, pitting on permanent teeth
22
Q

What gross pathologic lesions are seen with CDV?

A
  • Thymic atrophy (young puppies)
  • Bronchopneumonia, enteritis, pustular dermatitis
  • Hyperkeratosis f nose and footpads
23
Q

What Microscopic lesions are seen with CDV?

A
  • Necrosis of lymphatic tissues
  • Interstitial pneumonia
  • Inclusion bodies in respiratory, urogenital and gastrointestinal epithelium, WBC and RBC
  • Neuronal degeneration, gliosis, noninflammatory demyelination, perivascular cuffing, nonsuppurative leptomeningitis, inclusion bodies in glial cells and neurons
24
Q

How is CDV diagnosed?

A
  • Should be considered for any febrile condition in dogs with multisystemic manifestations
    • Unvaccinated dogs between 3-6 months of age at greatest risk
  • IFA, RT-PCR, Serum, IHC
  • Conjunctival, tracheal, vaginal or other epithelial smears
  • Buffy coat, urine sediment, bone marrow aspirate, feces VI generally not successful
  • Antibody detection (CSF, blood):
    • Higher titer in CSF vs blood - typical of natural infection
    • Elevated IgM levels
25
Q

What is the treatment for CDV?

A
  • Nonspecific, supportive treatment
    • prevent secondary bacterial infections
    • Fluid therapy
    • Managing neurologic manifestations (anticonvulsants)
  • With aggressive car, dogs may fully recover from multisystemic disease or may have long term neurologic signs
26
Q

What is the prognosis for CDV?

A
  • Poor prognosis for acute, progressive, or severe neurologic disease
27
Q

What is the CDV vaccination?

A
  • Core Vaccine - AAHA
  • Modified live virus vaccine
    • pups vaxed at 6wks, then every 2-4 wks until 16 wks of age
    • Booster at 1 year then every 3
    • NOT be used if pregnant or early-lactation
    • can produce illness in immunosuppressed dogs
  • Recombinant canarypox vector vaccine:
    • Licensed for use in dogs and ferrets
    • AAZV recommends etra-label use in zoo species
27
Q

What is the CDV vaccination?

A
  • Core Vaccine - AAHA
  • Modified live virus vaccine
    • pups vaxed at 6wks, then every 2-4 wks until 16 wks of age
    • Booster at 1 year then every 3
    • NOT be used if pregnant or early-lactation
    • can produce illness in immunosuppressed dogs
  • Recombinant canarypox vector vaccine:
    • Licensed for use in dogs and ferrets
    • AAZV recommends etra-label use in zoo species
28
Q

What is Newcastle Disease Virus?

A
  • Infectious disease of poultry and wild birds
    • >250 species susceptible
  • Worldwide distribution
  • Zoonotic - self-limiting conjunctivitis, mild flu-like symptoms
29
Q

What are the different strains of NDV?

A
  • Virulent strains - “exotic Newcastle Disease” in US
    • Reportable with trade restrictions
    • Mortality rate: 70-100%
  • Low virulence strains - mild clinical disease - Common in US
30
Q

How is NDV transmitted?

A
  • Direct or indirect contact with secretions and excretions from infected birds
    • inhalation +/- ingestion
31
Q

What are the virulent NDV strains?

A
  • Reportable
  • Viscerotrophic velogenic ND (VVND)
  • Neurotrophic velogenic ND (NVND)
  • Mesogenic
32
Q

What are the low virulence strains of NDV?

A
  • Used as live vaccines
  • Not reportable
  • Lentogenic
  • Asymptomatic lentogenic
33
Q

What are the clinical signs of NDV?

A
  • Torticollis
  • Eyelid edema
  • Weakness
  • Inability to rise
  • Eyelid hemorrhage
  • Foamy discharge
34
Q

What are the gross lesions associated with NDV?

A
  • Splenic necrosis
  • Pancreas necrosis
  • Tracheal mucosal hemorrhage
  • Intestinal necrosis and hemorrhage
35
Q

How is NDV diagnosed?

A
  • Oropharyngeal or cloacal swabs
    • RT-PCR or HI, Sequencing
36
Q

Are there vaccines for NDV?

A
  • Live low virulence strains
    • mass admin in drinking water
    • individual nares or conjunctival sacs
  • inactivated and vectored vaccines
37
Q

What viruses are part of the Genus Heniparvirus?

(family Paramyxoviridae)

A
  • Hendra virus (horses & humans)
  • Nipah virus (swine & humans)
38
Q

What is Hendra virus?

A
  • 1994 Hendra, Australia - outbreak of acute, febrile respiratory/neurologic disease with high lethality in horses (89%) and handlers (57%)
  • Flying foxes are reservoir hosts
  • Continued sporadic cases in E. Australia
  • Transmission generally NOT via aerosols
    • Body fluids from infected flying foxes - urine, placental fluids, other bodily fluids, tissues
39
Q

What is the pathogenesis of Hendra Virus?

A
  • Nasopharyngeal exposure ⇢ Replication in macrophages and bronchial ln ⇢ Disseminated in blood (primary consequences in lungs
    • Believed to be based on widespread vasculitis due to tropism of virus for vascular tissues
      *
40
Q

What are the clinical signs of Hendra virus?

A
  • Acute interstitial pneumonia
    • Frothy nasal discharge, respiratory distress, inappetence
  • Vasculitis, hemorrhage, and edema
  • Neurologic disease
    • Neuronal necrosis and focal gliosis
    • Ataxia, weakness, head tilt, recumbency, restlessness
41
Q

How is Hendra Virus diagnosed?

A
  • Suspect : acute onset of fever ⇢ rapid progression to death
  • Samples; Blood, nasal, oral, and/or rectal swabs
  • REPORTABLE - BSL-4 laboratory diagnosis

Virology (37 decks)

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