Ruminant Respiratory Diseases

Question 1

Describe the pathogenesis and clinical signs associated with BRSV

Answer 1

The virus is inhaled and replicates in the respiratory epithelium, it disperses through the URT and bro hi and syncytial spread through the bronchioles. Clinical signs - interstitial pneumonia and emphysema (severe in youngstock),

Question 2

Bovine respiratory syncytial virus is what type of virus?

Answer 2

Pneumovirinae

Question 3

What histological lesions are associated with BRSV?

Answer 3

Formation of multinucleated giant cell syncitia, may contain eosinophilic inclusion bodies

Question 4

What husbandry practices are associated with BRSV?

Answer 4

Winter housing, stress periods (mixing and during transport)

Question 5

Outline three ways in which BRSV can be diagnosed.. Describe findings.

Answer 5

PM - pulmonary atelectasis, emphysema in the caudal lungs, bronchoconstriction

Histo - giant cell syncitia with eosinophilic inclusion bodies

ELISA

Question 6

Which bovine respiratory pathogen is a paramyxoviridae?

Answer 6

Parainfluenza 3

Question 7

Outline the pathogenesis and clinical signs of Bovine PI-3

Answer 7

Pathogenesis - Virus infects the respiratory mucosa, ciliary clearance ceases, epithelial necrosis, secondary bacterial infection.

Clinical signs - Bronchitis, bronchiolitis, alveolar thickening and hyperplasia, intracytoplasmic inclusion bodies in the lung (around d 5-7)

Question 8

How can PI-3 be diagnosed and treated/ controlled ?

Answer 8

• Dx - iFAT, ELISA (from BAL/ dead tissue)
• Tx/ control - Improve management (hygiene), ensure adequate colostrum intake, vaccination

Question 9

Which respiratory pathogens form the Bovine Respiratory Disease Complex?

Answer 9

• BRSV
• BHV1 - IBR
• PI-3
• BVD

Question 10

Cows of what age are most susceptible to the Bovine Respiratory Disease Complex?

Answer 10

<6 months (2-10 wks usually)

Question 11

What clinical signs are associated with the Bovine Respiratory Disease Complex?

How can diagnosis be achieved?

Answer 11

• Cough
• > RR
• Nasal/ Lacrimal discharge
• Fever

Dx. NP swabs, BAL - viral isolation/ PCR

Question 12

IBR is caused by which type of virus?

Answer 12

Type 1 Herpes virus

Question 13

Outline the clinical signs assocaited with IBR.

Answer 13

1. Nasal discharge - progressive
2. Bronchopneumonia
3. > RR
4. Calves - mucosal ulcerative lesions in oesophafus and forestomach
5. High morbidity, low mortality
6. 6-18 month cattle

Question 14

Outline the sequelae of BVD during the 1st/2nd/3rd trimester of pregnancy.

Answer 14

1. Reproductive losses
2. Persistently infected calves
3. Foetus fight off virus

Question 15

Ovine pulmonary adenocarcinoma are associated with which type of virus?

What clinical signs are associated with the disease?

Answer 15

Retrovirus - Jaagsiekte

Clinical signs - ++ respiratory discharges, weight loss, progressive dyspnoea

Question 16

Which type of cell are targetted by Jaagsiekte?

Answer 16

Type 2 pneumocytes

Question 17

This small ruminant lentivirus causes pneumonia and wasting and is highly contagious and fatal. It takes years for clinical signs to manifest.

Outline its pathogenesis.

Answer 17

Maedi Visna

Virus is transmitted through respiratory route and infected colostrum/ milk. It infects monocytes and infiltrates lymphoid tissue and causes smooth muscle hyperplasia in the lung/

Question 18

Which mycoplasma has been shown to cause “cuffing pneumonia”, septic arthritis, otitis media and mastitis?

Answer 18

Bovis

Question 19

Describe what is meant by cuffing pneumonia.

Answer 19

Histologically there appears to be lymphocytic cuffing areound the small airways

Question 20

Name the species of Pasturellaceae which are relevant in cattle?

What are the morphological features of the Pasteurellaceae bacteria?

Answer 20

Mannheimia haemolytica, Pasteurella multocida, Histophilus somni

Morph - gram -ve bacilli/ coccobacilli, facultative anaerobes

Question 21

What clinical signs are associated with Pasturellaceae infections?

Answer 21

1. Fibrinous pleurisy/ intra-alveolar fibrin
2. Acute depression, lethergy, anorexia
3. Endotoxaemia
4. Sudden death
5. Increased RR + abdo involvement - laboured
6. Fever
7. Dehydration
8. < GI

Question 22

Systemic spread of Histophilus somni occurs where?

Answer 22

• Myocardium
• Pericardium
• Pleura
• Synoviae

Question 23

Shipping fever and bacterial infection secondary to IBR are often associated with which Pasturellaceae?

Answer 23

Mannheimia haemolytica

Question 24

How can Histophilus somni cause thrombus formation?

Answer 24

Lipoligossacharides provoke host inflammatory response, histamine release and thrombus formation.

Remember, its a commensal in the genital tract.

Question 25

Which antibiotics are used in the treatment of Pasturellaceae infection?

Answer 25

Oxytet

Flurfenicol

Tylosin

(remember NSAIDs aswell)

Question 26

Which bacterial species are associated with Pasturellosis in sheep?

Answer 26

Mannheimia haemolytica

Bibersteinia trehalosi

Question 27

Atypical pneumonia in sheep is associated with which bacterial species?

What clinical signs are seen with such infection?

Answer 27

Mycoplasma ovipneumoniae

• Non-progessive chronic pneumonia
• Chronic soft cough/ nasal discharge
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Question 28

What epidemiological features are associated with Pasturellosis infection?

How can infection be prevented?

Answer 28

1. Close contact
2. Age-mixing
3. Carriers
4. Poor ventilation
5. Poor immunity

Control - colostrum intake, housing and husbandry, vaccination