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3. Equine 2 > Viral diseases > Flashcards

Viral diseases Flashcards

1
Q

Equine Picornaviruses
- structure?
- important types?

A

▪ Single-stranded, positive-sense RNA
▪ Non-enveloped
▪ Aphthovirus
> Equine rhinitis virus A
▪ Erbovirus
> Equine rhinitis virus B 1
> Equine rhinitis virus B 2
> Equine rhinitis virus B 3

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2
Q

Equine rhinitis virus A & B - typical disease, geography

A
  • typically cause very mild resp disease
  • most horses infected before 6 months of age
  • usually we don’t care about this, often no clinical signs
    <><><><>
    ▪ ERAV
    > Endemic worldwide
    ▪ ERBV
    > 1 & 2- endemic worldwide
    > 3- Australia, UK, & Japan
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3
Q

Equine rhinitis virus A & B spread

A

Viral shedding
▪ ERAV
> Respiratory secretions
> Urine
▪ ERBVs
> Respiratory secretions only

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4
Q

Equine rhinitis virus A & B - clinical signs

A
  • may not have any, and if they do, generally mild
    ▪ Fever
    ▪ Serous-mucous nasal discharge
    ▪ Coughing
    ▪ Anorexia
    ▪ Pharyngitis
    ▪ Submandibular lymphadenopathy
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5
Q

Co-infections with ERBV

A
  • common to have multiple infections at the same time
  • EIV
  • EHV-1 or 4
  • ERAV
  • S. equi xx equi
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6
Q

Equine rhinitis virus A & B diagnosis, treatment, prevention

A

Diagnosis
▪ Nasopharyngeal swab
▪ Serology (paired)
<><>
Treatment
▪ Supportive care
<><>
Prevention (not easy)
▪ Isolation of new, young horses (but more for other diseases, eg. herpes, S. equi ss equi)
▪ Vaccination? does exist, but conditional license (not available in all circumstances): probably not necessary anyways

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7
Q

Equine Influenza
- type of virus, classifications?
- subtypes of importance?

A

▪ Orthomyxovirus > Single-stranded RNA
▪ Classifications > A, B, C & D
<><><><>
Subtypes IAV
▪ 1= H7N7
▪ 2= H3N8
> American: Florida
> Clade 1
> Clade 2
<><>
- types important for vaccination considerations

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8
Q

Equine
Influenza
▪ Transmission

A

▪ Aerosol → 1-2 km
▪ Droplets
▪ Fomites → 3 days
▪ Incubation period 1-3 days
▪ Viral shedding 10 days

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9
Q

what age groups get equine influenza? what about seasonality?

A
  • more positives in young adults (1-9 age) than in very young, or adults
  • more disease in spring, then winter, less in fall and summer
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10
Q

Equine Influenza clinical signs

A

Clinical signs
▪ Inappetance
▪ Fever
▪ Nasal discharge
▪ Cough
<><><><>
Uncommon signs
▪ Tachypnea
▪ Limb edema
▪ General weakness
<><><><>
- can have severe clinical signs, usually in naive populations or donkeys, mules…

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11
Q

Equine Influenza
▪ Diagnosis, treatment

A

▪ Nasopharyngeal wash
> Ideal sample
▪ Nasopharyngeal swab
▪ Nasal swab
▪ Paired serum titers
<><><><>
▪ Treatment
▪ Supportive care

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12
Q

Equine
Influenza
▪ Prevention

A

▪ Isolation of new horses
> 21 days
▪ Maintain good biosecurity
> Minimize shared items
> Decrease human and horse traffic
> Promote hand hygiene
▪ Vaccination

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13
Q

Is equine Influenza a zoonotic disease?

A

yes, but very uncommon - usually immunocompromised

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14
Q

Office of International
des Epizooties (OIE) tell us what about equine influenza

A
  • what strains should be contained in our vaccines, and what vaccines that are available meet this standard
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15
Q

Equine Herpesviruses
- what are the strains, and who do they affect?

A

▪ EHV 1-5= horse
▪ EHV 6-8= donkey
▪ EHV 9= zebra
<><><>
▪ Typically species specific
▪ Exceptions EHV-1 & 9

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16
Q

Equine Herpes Virus-1 & 4
- epidemiology: reservoirs, transmission, incubation

A

Reservoir
▪ Latently infected horses
<><>
Transmission
▪ Aerosol, droplets, and fomites
▪ Shed in nasal secretions
> 1-21 days post-infection
▪ Fetal and placental tissues
> High viral load
<><><><>
▪ Incubation period= 2-10 days

17
Q

EHV-1 and 4 pathogenesis

A

EHV-1:
▪ Enters respiratory epithelial cells
> Nasal and nasopharynx mucosa
▪ Within 24-48 hours
> Spreads to regional lymph nodes
> Mononuclear cells infected > this is how it moves through the body
▪ Within 4-10 days
> Cell-associated viremia (may or may not see fver at this point)
> Infection of endothelial cells
<><><><>
EHV-4 tends not to have cell-associated viremia, otherwise very similar

18
Q

EHV-1 & 4 viral latency frequency, locations

A

▪ >50% of cases post-infection
▪ Persists for life of host
<><><><>
Locations
▪ Trigeminal nerve
▪ Lymphoid cells

19
Q

EHV-1 & 4 clinical signs

A

▪ Fever
▪ Lethargy
▪ Anorexia
▪ Serous→ mucopurulent nasal discharge
▪ Serous ocular discharge
▪ Conjunctivitis
▪ Submandibular lymphadenopathy

20
Q

EHV-1 sequelae

A
  • this is what we are really worried about
    <><>
    Abortions
    ▪ 2-12 weeks after infection
    ▪ Final months of gestation
    <><><><>
    ▪ Fetal infection
    ▪ Chorioretinitis (can lead to blindness)
    ▪ Myeloencephalopathy: <10% of horses (ascending paresis)
21
Q

EHV-1 & 4 Dx

A

▪ Virus isolation (gold standard) > but typically to lengthy in time so we rely on PCR
> Nasopharyngeal lavage
> Leucocyte buffy coat isolation
▪ PCR/ qPCR (often what we use)
> Nasal swab
> Whole blood buffy coat
▪ Serology > also quite a wait between samples
> Paired titers
<><><><>
- need to interpret in context of clinical signs

22
Q

EHV-1 & 4 treatment and prevention

A

Treatment
▪ Supportive care
<><>
Prevention
▪ Elimination is not possible
▪ Isolation of new horses
> 21 days
▪ Maintain good biosecurity
> Minimize shared items
> Decrease human and horse traffic
> Promote hand hygiene
▪ Vaccination

23
Q

EHV-2 & 5 - what are these? when do they cause issues? latency and transmission?

A

▪ Gammaherpesviruses
▪ Infected at < 1 year of age
▪ Latency established
> EHV-2 = B-cells, macrophages, and Langerhans cells
> EHV-5 – B-cells, T-cells, and alveolar macrophages
<><><><>
▪ Transmission
> Viral shedding in nasal secretions

24
Q

EHV-2 & 5 - what symptoms does it cause?

A

Upper respiratory disease
▪ Nasal & ocular discharge
▪ Tachypnea
▪ Coughing
▪ Fever
▪ Submandibular lymphadenopathy
▪ Keratoconjunctivitis

25
Q

Equine multinodular pulmonary fibrosis
▪ Etiology, pathophysiology

A

▪ Highly likely Equine Herpes Virus-5
▪ Equine Herpes Virus-2 unknown
<><><>
Pathophysiology
▪ Unknown
▪ Equine respiratory cells not susceptible
▪ Direct infection of lymphocytes?

26
Q

EMPF
▪ Clinical signs

A

▪ Fever (intermittent)
▪ Lethargy
▪ Weight loss
▪ Tachypnea
▪ Coughing
▪ Poor performance
<><><><>
▪ Progressive

27
Q

EMPF diagnosis, diagnostic criteria

A

▪ Gold standard= post- mortem
<><><><>
Diagnostics criteria
▪ Progressive respiratory disease
+
▪ Multiple masses on thoracic imaging
+
▪ EHV-5 positive PCR on BAL
Or
▪ EHV-5 positive PCR on lung biopsy

28
Q

EMPF treament, prognosis

A

Treatment
▪ Anti-inflammatories
▪ Antimicrobials
▪ Anti-virals
▪ Supportive care
<><><><>
Prognosis
▪ Short-term survival (discharge) ~ 50%
▪ Long-term survival (>6 months) ~ 14%

29
Q

Equine viral arteritis
- cause, who maintains it?
- transmission?
- who gets it? signs?
- prevention?

A

▪ Equine arteritis virus
▪ Maintained in carrier stallions
<><>
Transmission
▪ Aerosolized respiratory secretions
▪ Venereal
<><><><>
Exposed, naïve mares
▪ 80-100% respiratory disease
> Serous nasal discharge
> Submandibular lymphadenopathy
> Cough
▪ Vasculitis
▪ Early embryonic death/ abortion
<><><><>
▪ Self-limiting infection
▪ MLV vaccine available

30
Q

African Horse Sickness
- cause?
- syndromes?
- forms?

A

▪ African horse sickness virus
<><><><>
Clinical syndromes
▪ Peracute
> Fever & severe pulmonary disease
▪ Acute (mixed)
> Edema of head/ neck, pulmonary
disease
▪ Subacute
> Fever, edema, myocardial dysfunction
▪ Mild
<><><><>
▪ Endemic
> Inactivated vaccine available
▪ Epidemic
> Eradication

31
Q

Hendra virus
- type of virus?
- human issue?
- reservoir?
- geography
- clinical signs
- treatment and prevention

A

▪ Paramyxovirus
▪ ZOONOTIC > high fatality rate!
▪ Reservoir= Australian flying foxes
▪ Queensland & New South Wales
<><>
Clinical signs:
▪ Fever
▪ Severe pulmonary disease
▪ Neurologic dysfunction
▪ Death in 1-3 days
<><><><>
▪ No treatment
▪ Vaccine-Equivac® HeV > it is very good!

3. Equine 2 (16 decks)

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