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Virology > IBR, PI-3, BRSV > Flashcards

IBR, PI-3, BRSV Flashcards

1
Q

What is Bovine Respiratory Disease Complex?

A
  • Bovine “ shipping fever”
  • Stress
  • Viral respiratory infections (various combinations)
    • IBR (Herpesviridae, Alphaherpesvirinae)
    • BVDV/Pestivirus (Flaviviridae)
    • Bovine Respiratory Syncytial virus [BRSV] (Pneumovirus)
    • Parainfluenza III [PI3] (Paramyxovirus)
  • Secondary bacterial infections
    • Mannheimia hemolytica, Pasturella multocida, Histophilus somnus, Mycoplams spp.
      • bronchopneumonia ⇢ fibrinous pleuropneumonia
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2
Q

What illnesses does Bovine Herpes Virus (BHV)-1 cause?

A
  • BHV - 1.1
    • Infectious bovine rhinotracheitis (IBR)
  • BHV - 1.2 (BHV - 1.2a; BHV 1.2b)
    • Infectious pustular balanoposthitis (IPB)
    • Infectious pus
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3
Q

What is the BHV Pathogenesis

A
  1. Replication in epithelial cells → Rhinotracheitis
  2. Systemic cell associated spread → encephalitis
  3. In females, infection of the fetus → abortion
  4. Establishment of latency in neurons (infected for 1st time)
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4
Q

What are the characteristics of a Primary Lesion of BHV

A
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5
Q

what do BHV genital lesions look like?

A
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6
Q

What do BHV esophageal lesions look like?

A
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7
Q

what does a nostril legion of IBR look like?

A
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8
Q

Is the mortality rate of IBR high or low?

A
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9
Q

What do IBR turbinate and esophageal lesions look like?

A
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10
Q

What does BHV induced conjunctivitis look like?

A
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11
Q

what is the relationship between, temperature, viral shedding, and immunological parameters

A
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12
Q

How are the hosts’ defenses escaped from?

A
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13
Q

How is BHV-1 transmitted?/Where is the virus shed?

A
  1. Placenta
  2. Artificial Insemination
  3. Animal to animal contact (eye/nose discharge)
  4. Venereal (semen/vaginal discharges)
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14
Q

What are characteristics of BHV-abortions?

A
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15
Q

What proportion of Bovine abortions are IBR?

A
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16
Q

What are risk factors for BRDC spread?

A

Risk factors most often found to facilitate a BoHV-1 infected herd were

  • herd size
  • Purchase of cattle
  • cattle density
  • age of cattle
  • distance to neighboring cattle herds and professional visitors
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17
Q

What are major complications of BHV-1 infection?

A
  1. Shipping Fever
  2. *Abortions
18
Q

What are epidemiologic concerns/factors of BHV?

A
  1. Found worldwide
    a. high seroprevalence
    b. high morbitity, low mortality
  2. Perpetuated in Cattle Populations
    a. ** latent infections, “hallmark of herpes viruses”
19
Q

What are common comorbidities to IBR?

20
Q

What ways can BHV be diagnosed?

A
  1. Polymerase chain reaction
  2. Virus isolation
  3. immunofluorescence
  4. Western Blot
  5. ELISA
  6. Neutralization test
  7. other tests
21
Q

What is the differential diagnosis of BHV-1

A
  1. Upper respiratory lesions
  2. Abortions
  3. Vaginitis
  4. Pneumonia (shipping fever)
  5. Larynx (calf diphtheria)
  6. BVDV (oral ulcers, diarrhea and no dyspnea)
  7. Keratitis (Pink eye)
22
Q

What types of BHV-1 vaccines are there?

A
  1. Live attenuated
    1. (intranasal/intramuscular)
  2. Heterologous vectors expressing BHV-1 Antigens
  3. Subunit/DNA
  4. Adjuvants
  5. Inactivated/Killed
    1. (Intramuscular)
  6. Combined approaches
23
Q

What are considerations of intranasal vs intramuscular vaccines?

24
Q

What are BHV-1 seroconversion rates of Attenuated vs Inactivated vaccines?

25
Q

What are types of Paramyxoviridae?

26
Q

What are characteristics of Paramyxo?

A
  • Enveloped
  • Genome - ssRNA, negative sense
  • Helical nucleocapsid with herring-bone appearance
27
Q

What is Parainfluenza virus 3 (PI3)?

28
Q

How is PI3 transmitted?

A
  1. Respiratory route via aerosolized secretions
  2. Serologic prevalence in cattle ranges from 60-90%
  3. Virus can be shed in nasal secretions for 8-10 days
29
Q

What is the PI3 Pathogenesis

A

Asymptomatic to interstitial pneumonia

  • Virus replicates in alveolar type 2 cells- decreases surfactant production
  • as a result the lungs don’t inflate easily
  • Results in consolidation (inflammation, atelectasis) of anterior lobes of lung

Decreased bacterial clearance

  • Lysis of respiratory epithelium
  • Infection of macrophages
30
Q

How PI3 leads to shipping fever

A
  1. Decreased bacterial clearance
  2. Along with BHV-1, BRSV and BVD - part of BRDC
  3. Secondary bacterial infections - shipping fever
31
Q

How do you protect against PI3?

A
  1. Short-lived immunity
  2. Vaccines
    1. No stand-alone PI3 vaccines
      1. Several, as part of complex
      2. PI3, BRSV, IBR, BVDV -MLV or Inactivated
    2. Incomplete protections, short-lived immunity
    3. Presence of maternal antibody can protect the calves but may affect the active immunization
32
Q

Paramyxoviruses chart

33
Q

What are the characteristics of Bovine respiratory synctytial virus (BRSV)

A
  1. Paramyxovirus
  2. ssRNA virus (- sense)
  3. enveloped
  4. similar virus present in humans
  5. Found worldwide
    1. prevalence in US ~65-80%
  6. Acute viral pneumonia
    1. interstitial pneumonia (often fatal)
  7. Secondary bacterial pneumonia
    1. Suppurative bronchopneumonia
34
Q

What are features of BRSV Pathogenesis

A
  1. BRSV is transmitted by aerosolized secretions absorbed in respiratory tract
  2. Primary replication in the nasal epithelium then upper respiratory tract and bronchial tree
  3. Infection of epithelial cells of terminal airways (syncytia), alveolar macrophages
  4. Inflammation - broncho-interstitial pneumonia, necrotizing bronchiolitis
  5. Expiration blocked - emphysema
  6. Immune-mediated damage – edema
  7. Secondary bacterial infection (common BRD agents)
35
Q

What are post mortem findings of BRSV?

36
Q

How do you diagnose BRSV?

37
Q

What are BRSV clinical findings?

A
  1. Fever (104 - 108 F), mucoid nasal discharge, salivation
  2. Increased rate of respiration, ~respiratory distress, mouth breathing, dyspnea
  3. Auscultation - lower respiratory disease
    1. Findings dependent + upon bacterial infection
      1. infection with virs only → interstitial emphysema, small airway disease, expiratory dyspnea
      2. infection with secondary bacterial infections → crackles/wheezes
38
Q

What is a typical BRSV scenario?

A
  1. weaned for 4-6 weeks
  2. previously gaining weight
  3. “cold snap” or sudden weather change
  4. feed consumption drops
  5. calves standing aside - head lowered, nasal/ocular discharge, fever, cough/progressive dyspnea
  6. 0-20% mortality rate
39
Q

BRSV quick facts, Epidemiology & Transmission

A
  1. Ubiquitous virus with exposure occurring in most cattle at an early age. (60-80% seroprevalence)
  2. Most common cause of outbreaks of respiratory disease in young dairy calves
    1. Dairy calves most susceptible (2 wks - 9 mnths old), beef calves (6 wks - 13 mnths)
  3. Repeated seasonal outbreaks (fall and winter) even in closed herds
  4. Virus in aerosol or droplets of respiratory excretions
  5. Fatal infections can occur in naive cattle of all ages - is rare
  6. Attenuation of clinical disease in calves with high maternal antibody
  7. Adult carriers
40
Q

What are steps for BRSV Prevention?

A
  1. Good Husbandry
    1. Well ventilated housing
    2. In US BRSV incidence is higher in northern states in winter than elsewhere
  2. Vaccination: strain variation
    1. Killed BRSV vaccines
      1. do not elicit high levels of VN or anti-fusion antibody
    2. Modified-Live BRSV vaccines
      1. Some vaccines still get mild to moderate disease
      2. Decrease in disease in groups with two vaccinations

Virology (37 decks)

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