Chapter 11 Flashcards

1
Q

What are the three subfamilies of the family Herpesviridae?

A

Alphaherpesvirinae
Betaerpesvirinae
Gammaherpesvirinae

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2
Q

How would you classify the speed of replication and killing in the Alphaherpsevirinae subfamily?

A

rapid

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3
Q

What do latent infections of Alphaherpesvirinae usually involve?

A

the sensory nerve ganglia

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4
Q

How would you classify the speed of replication and killing in the Betaherpesvirinae subfamily?

A

slow

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5
Q

Where are Betaherpesvirinae latent infections localized?

A

in secretory epithelial cells

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6
Q

Where do Gammaherpesvirinae viruses replicate and establish latency?

A

in lymphocytes

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7
Q

Name 5 key features of all herpesviruses.

A
  1. Enveloped
  2. Produce both acute and latent infecctions
  3. Clinical signs and pathology extremely variable
  4. Susceptible to antiviral drugs
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8
Q

What type of virus, genomically, is herpesvirus?

A

The genome is linear, double-stranded DNA, 125-235kbp

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9
Q

For herpesvirus replication, where does DNA replication and encapsidation occur?

A

in the nucleus

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10
Q

What are the multisystemic alpha-herpesviruses of veterinary importance?

A

Equine herpesvirus 1 and 4
Bovine herpesvirus 1 and 5
Marek’s disease virus
Pseudorabies virus

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11
Q

What disease forms do EHV-1 cause?

A

reproductive, neurological, and/or respiratory disease

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12
Q

What disease form does EHV-3 cause?

A

equine coital exanthema

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13
Q

What disease forms does EHV-4 cause?

A

mainly respiratory

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14
Q

What cells does EHV-1 infect?

A

respiratory epithelial cells, endothelial cells, neuronal cells, and lymphoid cells

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15
Q

What cells does EHV-4 infect?

A

epithelial cells, neuronal cells

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16
Q

Which equine herpesvirus is most commonly associated with respiratory disease?

A

EHV-4

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17
Q

Classify respiratory disease caused by EHV-4.

A

It is an acute upper respiratory infection that is usually self limiting. There is mild to moderate fever and nasal discharge

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18
Q

What animals are susceptible to a lower respiratory infection caused by EHV-4?

A

neonates, immunocompromised, or naive young animals

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19
Q

Which equine herpesvirus is most commonly associated with abortion?

A

EHV-1

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20
Q

When does abortion due to EHV-1 usually occur?

A

During the last four months of gestation, but can occur as early as the 4th month

Note: Equine gestation is approximately 11-12 months

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21
Q

If a foal is born to a mare that has EHV-1 (non-latent), what typically occurs to the foal?

A

it dies shortly after birth

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22
Q

What important virus characteristics does EHV-1 have that are associated with abortion?

A
  1. Replication in endothelial cells and lymphocytes

2. Ability to invade allantochorion resulting in placental and fetal ischemia.

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23
Q

What lesions are typically found on fetuses that were aborted due to EHV-1?

A

They contain microscopic lesions, which include bronchiolitis, pneumonitis, splenic, and hepatic necrosis, and intranuclear inclusion bodies

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24
Q

What equine herpesvirus causes equine herpes myeloencephalitis?

A

EHV-1

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25
Q

What premonitory signs do patients with equine herpes myeloencephalitis have?

A

only fever

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26
Q

What symptoms are associated with equine herpes myeloencephalitis?

A

neurological dysfunction ranges from mild ataxia and paresis to complete paralysis and recumbency

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27
Q

What is the prognosis of equine herpes myeloencephalitis?

A

Prognosis is favorable if non-recumbent; recumbent horses frequently develop fatal complications

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28
Q

What distinguishes the hypervirulent strain of EHV-1 from other strains?

A

The hypervirulent strain of EHV-1 causes high morbidity and case fatality rates, are highly resistant to vaccination, affect horses of all breeds, ages, and vaccine status, and have up to a 10-fold increase in virus replication

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29
Q

How do EHV-1 and EHV-4 enter the horse?

A

via nasopharyngeal mucous membranes

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30
Q

How does EHV-1 spread systemically?

A
  1. The virus spreads to cells underlying lamina propria
  2. The virus replicates in the regional lymph nodes
    3a. Cell-associated viremia - virus is disseminated in CD8+ lymphocytes
    3b. Virus disseminated to uterine and CNS vascular endothelium
    3c. Virus disseminated to neurons of trigeminal nerve with persistent latent infection of trigeminal ganglino
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31
Q

EHV-1 readily infects endothelial cells. What does this infection result in?

A

Infection of placental endothelium - abortion

Infection of neuronal endothelium - myelopathy, encephalopathy, myeloencephalopathy

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32
Q

Where do EHV-1 and EHV-4 hibernate (latent phase)?

A

Mainly in neuronal cells located in the sensory ganglia innervating the nasopharyngeal mucosa
EHV-1 can establish latency in T-lymphocytes

33
Q

What conditions can reactivate latent EHV-1 and EHV-4 infections?

A

stress associated with pregnancy, transport, racing, and training

34
Q

How do reactivated equine herpesvirus infections impact the epidemiology of these viruses?

A

The reactivated infections are usually inapparent and can be spread to other horses without notice

35
Q

what does a young horse’s initial infection of equine herpesvirus usually coincide with?

A

declining maternal antibody

36
Q

What are the differentials to consider for the respiratory form of EHV-1 or EHV-4?

A
  1. Influenza
  2. Respiratory form of equine viral arteritis
  3. Rhinovirus
37
Q

What are the differentials to be considered for the neurological form of EHV-1 or EHV-4?

A
  1. Wobblers (cervical stenotic myelopathy)
  2. Equine degenerative myelitis
  3. Equine protozoal myeloencephalopathy
  4. Trauma
  5. Arboviral encephalidites
38
Q

How is EHV-1 and EHV-4 diagnosed (tests)?

A

Viral isolation
Immunohistochemistry
Serology
PCR

39
Q

What are the shortcomings of vaccine efforts against EHV-1?

A
  1. Protection is not complete and is short-lived
  2. Maternal immune components will interfere with vaccination
  3. The vaccines generally do not prevent infection, but reduce the severity of clinical disease
40
Q

What is bovine herpesvirus type 1 (BHV-1) the etiologic agent of?

A
  1. Infectious bovine rhinotracheitis (IBR)
  2. Bovine coital exanthema
  3. Infectious pustular vulvovaginitis
41
Q

Why can’t infectious bovine rhinotracheitis (IBV) and infectious pustular vulvovaginitis (IPV) occur concurrently?

A

Because they do not come from the same strain of BHV-1

42
Q

What is bovine herpesvirus type 5 (BHV-5) the causative agent of?

A

neurological disease

43
Q

What are the five different presentations/disease manifestations of BHV-1?

A
  1. Respiratory disease
  2. Abortion
  3. Vulvovaginitis and balanoposthitis
  4. Perinatal mortality
  5. Keratoconjuntivitis
44
Q

What is the most economically important disease manifestation of BHV-1?

A

respiratory disease

45
Q

What is the portal of entry for BHV-1 and BHV-5?

A

the nasopharyngeal mucous membranes

46
Q

If BHV-1 crosses from the mother to the fetus, what happens?

A

abortion

47
Q

What differentials should be considered when considering BHV-1?

A
  1. Bovine respiratory syncytial virus (BRSV)
  2. Parainfluenza-3 viurs (PI-3)
  3. Bovine Viral Diarrhea viurs (BVD)
  4. Malignant catarrhal fever (MCF)
48
Q

For both EHV and BHV, when must virus isolation samples be collected?

A

early

49
Q

True or False: Unlike EHV, the vaccination for BHV prevents infection.

A

False: Vaccination does not prevent infection, but will ameliorate clinical disease and/or reduce number of events in an outbreak situation

50
Q

What causes Marek’s disease?

A

Gallid Herpesvirus 2

51
Q

How have clinical signs and the severity of disease associated with infection by Gallid herpesvirus 2 changed (1905-2005)?

A

The severity of disease has only increased since 1905 - It was orginally chronic and sporadic, but now is acute and aggressive
1905 - Classified as chronic polyneuritis
1915 - Immunosuppression was added to the list of clinical signs
1925 - Visceral lymphoma was added to the list of clinical signs
1975 - Transient paralysis was added to the list of clinical signs
1985 - Acute brain edema and acute rash were added to the list of clinical signs

52
Q

How many pathotypes of Gallid Herpesvirus 2 are there and what are they called?

A
4
Mildly virulent (M), Virulent (V), Very virulent (VV), and Very Virulent Plus (VV+)
53
Q

What are the 4 arbitrary phases of infection of poultry with Marek’s disease virus?

A
  1. Early productive-restrictive virus infection causing primarily degenerative changes
  2. Latent infection
  3. A second phase of cytolytic, productive-restrictive infection coincident with permanent immunosuppression
  4. A proliferative phase involving nonproductively infected lymphoid cells
54
Q

Where does the initial replication of Marek’s disease occur?

A

in the epithelial cells of the respiratory tract

55
Q

What differentials should also be considered when considering Marek’s disease?

A
  1. Avian leukosis virus

2. Retoci;pendotheliosis virus

56
Q

What causes pseudorabies?

A

Suid herpesvirus-1

57
Q

What is the primary host and reservoir of pseudorabies?

A

swine

58
Q

What species can be affected by suid herpesvirus-1?

A

cattle, dogs, cats, sheep, goats, raccoons, skunks, rodents, and others

59
Q

Pseudo rabies is _____ to non-swine species.

A

fatal

60
Q

True or False: Pseudorabies is reportable.

A

true

61
Q

What does stage 5 mean in terms of the PRV eradication program?

A

PRV free

62
Q

What does canine herpesvirus-1 cause?

A

Hemorrhagic disease of pups

63
Q

What clinical signs are associated with canine herpesvirus 1?

A

Painful and persistent crying, abdominal pain, depression, and anorexia

64
Q

How do dogs become infected with canine herpesvirus 1?

A

Their oronasal epithelium is infected either from the dam’s vagina or other infected dogs

65
Q

What is the ideal temperature for canine herpesvirus 1 replication?

A

Between 33-35 C (91.4 - 95 F)

66
Q

What role does hypothermia play in the pathogenesis of hemorrhagic disease in pups?

A

Hypothermia can lead to generalized, often fatal disease because:

  1. Puppies cannot temperature regulate
  2. Their rectal temperature is lower than adult dogs
  3. They are unable to mount a fever for protection
  4. They have suppressed cell-mediated immune responses
67
Q

What cell type is canine herpesvirus 1 cell associated viremia associated with?

A

macrophages

68
Q

What is the significance of Herpesvirus-B for humans?

A

They can only get it from bites by rhesus or other macaque monkeys and it often leads to fatal encephalitis

69
Q

What three herpes viruses of veterinary importance are betaherpesviruses?

A

Porcine herpesvirus-2
Feline herpesvirus 2
Bovine herpesvirus 4

70
Q

What is the one veterinary disease that is of any real significance in the gammaherpesvirinae subfamily>

A

Malignant Catarrhal Fever (MCF)

71
Q

What is MCF caused by?

A

Viruses that belong to the rhadinovirus genus
The two main viruses that are closely related genetically, that cause indistinguishable diseases are: Alcelaphine herpesvirus type 1 and Ovine herpesvirus 2

72
Q

Where does Alcelaphine herpesvirus type 1 occur mainly?

A

in Africa or in zoos or game farms that house the wildebeest

73
Q

What are the susceptible species of MCF?

A

cattle, bison, some species of deer, certain other exotic and domestic ruminants
bison and deer are more susceptible than cattle

74
Q

What are the carrier species of MCF?

A

Wildebeest and sheep

75
Q

Do the carrier species of MCF show clinical signs?

A

no

76
Q

MCF is often, but not always, ____.

A

fatal

77
Q

What differentials should be considered alongside MCF?

A
  1. BVD/mucosal disease
  2. Severe IBR
  3. Rhinderpest
  4. FMD
    5, Vesicular stomatitis
78
Q

What signs are associated with pseudorabies virus infection in cats and dogs?

A

There is usually frenzy associated with intense pruritus, paralysis of the jaws, pharynx, salivation, and howling