Individual Approach To Bovine Pneumonia

Question 1

what is the estimated cost of bovine pneumonia

Answer 1

Cost estimated at £60-80 million in UK

Treatment costs

Deaths

Reduced performance

Opportunity

£30-80/case

£500 cost per case if die

Question 2

what are major risk periods for bovine resp disease

Answer 2

Up to first 24 months of life

• Especially first 6-9 months

Housed dairy calves

Suckled calves at housing

Following transport/market

Question 3

how is BRD a multifactorial problem

Answer 3

Question 4

what history questions are important in the individual animal showing signs of resp disease

Answer 4

Individual animal or group?

Previous episodes and treatment?

Housed or at grass?

Question 5

what are the subjective signs of BRD

Answer 5

Dull/depressed

Increased respiratory rate (tachypnea)

Increased respiratory rate (hyperpnea)

Ocular discharge

Nasal discharge

Mouth breathing (dyspnea)

Coughing

Question 6

what are the objective signs of BRD

Answer 6

Increased temperature (pyrexia)

Harsh lung sounds/adventitious noise

Noise from URT

Question 7

what are viral BRD agents

Answer 7

Infectious Bovine Rhinotracheitis (IBR)

Parainfluenza virus (PI3)

Respiratory syncytial virus (RSV)

Bovine viral diarrhea virus (BVD)

Question 8

what are bacterial agents of BRD

Answer 8

Mannheimia hemolytica

Pasteurella multocida

Histophilus somni

Mycoplasma disbar

Mycoplasma bovis

Question 9

what are parasitic agents of BRD

Answer 9

Dictyocaulus viviparus (lungworm)

Question 10

how is diagnosis of BRD made

Answer 10

Based on history, clinical signs and recorded level of morbidity and/or one or more of following:

• Serology: of > 6 cases (paired samples 3 weeks apart)
• Pathogen culture and/or identification:
  
  • Nasopharyngeal/ocular swabs
  • Bronchoalveolar lavage
• Postmortem examination:
  
  • +/- virus identification
  • +/- bacteriology
  • +/- histopathology

Question 11

what is bronchioalveolar lavage (BAL) most useful for

Answer 11

Case selection (early)

Most useful for virus isolation (PI3, RSV) not IBR

Bacteriology limited

Only part of approach

Question 12

what are the costs of diagnostics

Answer 12

Ranges from £17-£100/animal depending on test

Question 13

what are the classifications of pneumonia

Answer 13

Chronic ‘cuffing’ (mycoplasma) pneumonia

Enzootic pneumonia — ‘viral pneumonia’

Infectious bovine rhinotracheitis (BHV-1)

Pneumonic pasteurellosis — ‘transit fever’

Patristic bronchitis — ‘husk’

Chronic suppurative pneumonia — ‘respiratory cripples’

Question 14

what is chronic cuffing (mycoplasmal) pneumonia

Answer 14

Various (low grade) mycoplasmas:

• Mycoplasma dispar
• Mycoplasma bovirhinis
• Ureaplasma diversum

Question 15

what does the mild form of chronic cuffing (mycoplasmal) pneumonia cause

Answer 15

occasional cough

tachypnea

Question 16

what does the severe form of chronic cuffing (mycoplasmal) pneumonia cause

Answer 16

Frequent cough

Tachypnea (>60 breaths/min)

Hyperpnea

Decreased exercise tolerance

Decreased growth rate

Adventitious sounds over cranioventral lung fields

Pyrexia (<39.5ºC, 103ºF)

Question 17

what is the morbidity of chronic cuffing pneumonia

Answer 17

up to 100%

Question 18

what is the mortality of chronic cuffing pneumonia

Answer 18

rare to get deaths

may resolve in mild cases without treatment

can predispose to secondary bacterial infection

Question 19

what are the appearance of the lungs in mycoplasma bovis infections

Answer 19

small abscesses throughout the lung that have the appearance of scattered rice

Question 20

what type of pneumonia does mycoplasma bovis cause

Answer 20

necrotizing pneumonia

well demarcated foci of caseous necrosis

Question 21

what are the differences in lesions of mycoplasma bovis and mannheimia hemolytica and histophilus somni

Answer 21

lesion is more circular and friable than foci of necrosis due to mannheimia hemolytica or histophilus somni

Question 22

which pathogen causes joint lesions

Answer 22

mycoplasma bovis in ~50% of calves

The carpus (knee) and stifle are the most commonly affected joints, but any joint can be involved. Calves can be lame in one or more joints.

Question 23

what pathogen would cause these lesions

Answer 23

mycoplasma bovis

microabscesses seen

Question 24

how does mycoplasma bovis cause infection

Answer 24

For most calves, illness from Mycoplasma starts when the bacteria colonizing the nasal passages multiplies rapidly

Stress – in the form of weaning, long transportation, co-mingling, and adverse weather conditions – increases cortisol in the calf’s bloodstream. This hormone inhibits the immune cells that normally keep bad bacteria confined to the nose

The bacteria move down into the windpipe and larger airways, where they directly damage the ciliated lining of the airways

Inflammation in the lungs leads to necrotic areas (areas of tissue death), and now signs of pneumonia in the animal such as increased respiratory rate, cough, and fever are detectable

Question 25

what pathogen is the likely cause of these lesions

Answer 25

mycoplasma bovis caseous necrotic lesions

Question 26

describe the pathologic changes that mycoplasma bovis causes

Answer 26

cranioventral lung consolidation presence of multiple dry and crumbly foci of caseous necrosis within these affected lungs histologically characterised by peribronchiolar lymphoid hyperplasia or ‘cuffing’, often accompanied by suppurative bronchiolitis and thickening of the interlobular septa, which are sometimes similar to lesions seen in CBPP otitis media in calves, as evidenced by ear drooping and headshaking, is an early sign of infection with M bovis, which leads later to pneumonia

Question 27

what are the signs of acute enzootic (viral) pneumonia

Answer 27

Dull Anorexic Tachypneic (up to 100 breaths/min) Hyperpneic Pyrexia (39.5-41.0ºC, 103-106ºF) Nasal discharge Frequent coughing Fluid sounds and crackles over cranioventral lung areas Progressive ill thrift and weight loss ‘Respiratory cripples’ — chronic suppurative pneumonia

Question 28

what pathogen is lthe likely cause of this lesion

Answer 28

infectious bovine rhinotracheitis causing acute laryngeotracheitis

Question 29

what pathogen causes shipping fever

Answer 29

pasteurellosis

Question 30

what is the peak incidence of pasteurellosis

Answer 30

sept-dec in weaned beef calves

Question 31

what pathogens can be involved in pasteurellosis (shipping fever)

Answer 31

can be multiple pathogens Mannheimia hemolytica Pasteurella multocida Histophilus somni

Question 32

how is pasteurellosis diagnosed

Answer 32

history clinical signs +/- BAL swab

Question 33

what is the pathogenicity of mannheimia hemolytica

Answer 33

Initiating agent of pneumonic pasteurellosis Pneumonia reproduced in experimental studies Strains A1 and A6 Present in nasal cavity of healthy carriers Mixing of carriers and susceptible animals precipitates pneumonia

Question 34

how is mannheimia hemolytica diagnosed

Answer 34

Broncho-alveolar lavage Lung lesions at postmortem examination Tonsillar and nasal isolates (not always pathogenic strains) Isolation difficult from animals treated with antibiotics Serology can be performed: * Paired samples (one sample taken when the animal is acutely ill and another taken 21 days later once it has recovered. The samples are tested together to ensure the validity of the results, and specific titre elevations between acute and convalescent samples indicate seroconversion)

Question 35

what is the pathogenicity of pasteurella multocida

Answer 35

Present in nasal cavity of most cattle Secondary pathogen: colonizes lesions induced by other agents (mycoplasmas, viruses) Some strains are primary pathogens (Type B) Readily isolated from lung lesions of untreated animals (isolates from upper respiratory tract may not be significant)

Question 36

what are the clinical signs of pasteurellosis

Answer 36

Dull Anorexic Tachypneic (60-100 breaths/min) Hyperpneic Pyrexia (up to 42ºC, 108ºF) and nasal discharge Adventitious lung sounds and coughing are not as marked as in enzootic pneumonia and may be absent

Question 37

what is the pathogenicity of histophilus somni

Answer 37

Present in upper and lower respiratory tracts of some healthy cattle Thromboembolic meningoencephalitis (rare in UK) Isolated from calf pneumonia in UK * Difficult to isolate * Transport medium

Question 38

how is pneumonic pasteurellosis treated and controlled

Answer 38

As for calf pneumonia Control: * Decrease stress * Vaccination: specific Mannheimia vaccines * Viral vaccines (RSV, PI3, BHV-1, BVDV)

Question 39

what is chronic suppurative pneumonia

Answer 39

inevitable end point in many cases repeated bouts of acute pneumonia

Question 40

what are the signs of chronic suppurative pneumonia

Answer 40

reduced weight gain/fail to gain weight

Question 41

what is the treatment of chronic suppurative pneumonia

Answer 41

treatment often unsuccessful: cull

Question 42

what is shown here

Answer 42

chronic suppurative pnuemonia

Question 43

what is shown here

Answer 43

chronic suppurative pnuemonia mucopurulent exudates in bronchioles

Question 44

what antimicrobials are available to use in the treatment of pneumonia

Answer 44

Oxytetracycline Amoxycillin +/- clavulanic acid Tylosin Spectinomycin Tilmicosin (Micotil) Ceftiofur (Excenel) Cefquinome (Cephaguard) Florfenicol (Nuflor) Enrofloxacin (Baytril) Danofloxacin (Advocin) Marbofloxacin (Marbocyl) Tulathromycin (Draxxin) Gamithromycin (Zactran) Tildipirosin (Zuprevo)

Question 45

what questions should you ask when you are deciding what antimicrobial to use (10)

Answer 45

Are the probable pathogens likely to be sensitive to the antimicrobial in vitro? Can the product be expected to reach therapeutic concentrations in the infected tissues for a sufficient period of time? Is the antimicrobial available in a preparation which is licensed for use in this class of animal? Is the route of administration appropriate to this animal and dose the dosing interval suit the current management situation? What are the required minimum withdrawal periods and are meat and/or milk residues likely to be a problem? Are there any risks to human health in the use of this product? Have I had previous success when using this product? Have animals on the same farm previously shown a good clinical response to treatment with the product? What is the cost of the product? What is the likely cost-benefit of using the product?

Question 46

which animals should you treat

Answer 46

Sick animals + ? Threshold temperatures (39.6ºC) * Labour intensive and not widely practiced In contact cohort? (metaphylaxis?) Decision is often arbitrary

Question 47

what additional therapy can be used to treat pneumonia

Answer 47

NSAIDs: * Flunixin * Ketoprofen * Carprofen * Meloxicam * Tolfenamic acid Vaccination in the face of an outbreak (IBR) Corticosteroids (Antihistamines) (Clenbuterol) Bromhexine (mucolytics) Fluids/diuretics TLC

Question 48

what are management factors that can be used

Answer 48

Adequate colostrum Housing design and management Cleaning and disinfection Timing of routine procedures * Castration * Weaning Stable group structures Vaccination protocols (pre-conditioning) “Prophylactic antimicrobials” (ex. Draxxin)