10 – Pneumonia (Ruminants, Swine) Flashcards
1
Q
Shipping fever in cattle
A
- *most common economically in Canada
- Typically pattern is naïve stressed calves that are mixed with other calves
o Viral infections reduce respiratory defenses
o Secondary bacterial infections then lead to bronchopneumonia
2
Q
Shipping fever ‘steps’
A
- Stress (ex. off pasture into feedlots)
- Immune suppression
- Viral infection
- Impaired defenses: get secondary infection with a bacteria
- Bronchopneumonia
*tend to not notice it until have bronchopneumonia
3
Q
Bronchopneumonia (cows): ‘pneumonic pasteurellosis’ grossly
A
- cranio-ventral consolidation
- fibrinopurlent exudate in airways and possibly pleura
- red to purple to black discoloured lobules
- widened intra-lobular septa
- areas of necrosis
4
Q
3 bacteria that are most commonly involved in bronchopneumonia
A
- Mannheima haemolytica
- Histophilus somni
- Pasteurella multocida
5
Q
Clinical signs of bronchopneumonia in cattle
A
- Fever
- Depression
- Anorexia
- Possible increased respiratory rate
- Coughing
- Nasal discharge
- *if concurrent tracheitis=probably combined infection with IBR
6
Q
Notes about culture for bronchopneumonia
A
- Treatment with antibiotics can result in negative culture
- H. somni: wimpy bacteria and often overgrown by other bacteria before testing complete
- Sampling best done at edges of lesions
o Centers can be colonized by secondary bacteria (Trueperella pyogenes)
o May lead to chronic pneumonias
7
Q
What are the viruses that can lead to pneumonias in cattle?
A
- IBR
- Bovine respiratory syncytial virus (BRSV)
- Coronavirus
- Parainfluenza
8
Q
Viral infections
A
- Usually associated with a stressor
- Secondary infections are common (clinical signs not seen until this)
9
Q
Viral infections: lesions
A
- *most typical of a bronchointerstitial pneumonia
- Cranioventral atelectasis
- Rubbery firmer texture to the lung
- Emphysema particularly in the dorsal lobes
- Lung fail to collapse normally
10
Q
Diagnosis of viral infections
A
- Histology or virus isolation
- *by time of sampling, viral disease is gone or masked by SECONDARY bronchopneumonia
11
Q
Mycoplasma bovis
A
- Cause of chronic pneumonia and polyarthritis syndrome
- Often seen with other pneumonias
- Occurs later in calves (compared to bronchpneumonias)
- Abscesses
- Ex. bison: huge damage=entire lung is a sequestrum
12
Q
Characteristic features of mycoplasma bovis
A
- Development of multifocal areas of caseous necrosis
- Abscesses
- Sequestrums
- *cranioventral lung lobes
13
Q
Toxic lung disease: 3-methylindole toxicity (fog fever): ‘steps’ (CATTLE)
A
- Lush green pasture (high levels of tryptophan) *within a few days
- Conversion in rumen to 3 methylindole
- Transport via blood where Clara cells and type II pneumocytes convert to a toxic intermediate
- Destruction of type I pneumocytes
- *Interstitial pneumonia, massive edema and emphysema
14
Q
Lesions with toxic lung disease
A
- Diffuse pulmonary edema
- Emphysema
- Heavy rubber lungs
- *other possible toxins and direct irritant gases can result in alveolar epithelial damage and similar gross signs
15
Q
Emphysema
A
- Air outside out of alveoli
- ‘gas leaks’ out into intralobular septa
16
Q
Interstitial pneumonia of feedlot cattle
A
- Disease similar to 3-methylindole toxicity
- Underlying cause is UNKNOWN (feed releated)
- Seen sporadically in S. Alberta
17
Q
Dictyocaulus viviparus (lungworm)
A
- More common in cooler, wetter climates
- Worms visible in bronchi of caudal lobes