IBR, PI-3, BRSV

Question 1

What is Bovine Respiratory Disease Complex?

Answer 1

• 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

Question 2

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

Answer 2

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

Question 3

What is the BHV Pathogenesis

Answer 3

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)

Question 4

What are the characteristics of a Primary Lesion of BHV

Answer 4

Question 5

what do BHV genital lesions look like?

Answer 5

Question 6

What do BHV esophageal lesions look like?

Answer 6

Question 7

what does a nostril legion of IBR look like?

Answer 7

Question 8

Is the mortality rate of IBR high or low?

Answer 8

Question 9

What do IBR turbinate and esophageal lesions look like?

Answer 9

Question 10

What does BHV induced conjunctivitis look like?

Answer 10

Question 11

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

Answer 11

Question 12

How are the hosts’ defenses escaped from?

Answer 12

Question 13

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

Answer 13

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

Question 14

What are characteristics of BHV-abortions?

Answer 14

Question 15

What proportion of Bovine abortions are IBR?

Answer 15

Question 16

What are risk factors for BRDC spread?

Answer 16

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

Question 17

What are major complications of BHV-1 infection?

Answer 17

1. Shipping Fever
2. *Abortions

Question 18

What are epidemiologic concerns/factors of BHV?

Answer 18

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

Question 19

What are common comorbidities to IBR?

Answer 19

Question 20

What ways can BHV be diagnosed?

Answer 20

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

Question 21

What is the differential diagnosis of BHV-1

Answer 21

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)

Question 22

What types of BHV-1 vaccines are there?

Answer 22

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

Question 23

What are considerations of intranasal vs intramuscular vaccines?

Answer 23

Question 24

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

Answer 24

Question 25

What are types of Paramyxoviridae?

Answer 25

Question 26

What are characteristics of Paramyxo?

Answer 26

- Enveloped - Genome - ssRNA, negative sense - Helical nucleocapsid with herring-bone appearance

Question 27

What is Parainfluenza virus 3 (PI3)?

Answer 27

Question 28

How is PI3 transmitted?

Answer 28

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

Question 29

What is the PI3 Pathogenesis

Answer 29

_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

Question 30

How PI3 leads to shipping fever

Answer 30

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

Question 31

How do you protect against PI3?

Answer 31

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

Question 32

Paramyxoviruses chart

Answer 32

Question 33

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

Answer 33

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

Question 34

What are features of BRSV Pathogenesis

Answer 34

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)

Question 35

What are post mortem findings of BRSV?

Answer 35

Question 36

How do you diagnose BRSV?

Answer 36

Question 37

What are BRSV clinical findings?

Answer 37

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

Question 38

What is a typical BRSV scenario?

Answer 38

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

Question 39

BRSV quick facts, Epidemiology & Transmission

Answer 39

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

Question 40

What are steps for BRSV Prevention?

Answer 40

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