Exam 2: Respiratory disease Flashcards
What is required to set up a disease?
3 Prongs
- Microbiological agents (pathogen)
- Environment
- Host
What makes a host susceptible to disease?
- Stress: increased cortisol levels
- Age: Don’t mix old with the young
- Immune status
- Nutrition
- Production type/stage
- Breed
- Previous exposure
- Origin
- Genetics
- Sex
- Disposition
- Weight
How does the environment make an animal susceptible to disease?
- Weather: Hot, cold, wind, mud
- Altitude
- Herd: Pregnant, weaning, social structure
- Housing
How does the pathogen (microbiological agent) make an animal more susceptible to disease?
- Pathogen profile
- Host
- Virulence
- Number/ amount
- Mode of transmission
How does respiratory disease set in?
- Initial viral infection (most, not all, respiratory diseases start with a viral infection)
- Virus attacks the muco-ciliary elevator (deactivates the cilia): First line of defense
- Secondary bacterial infection results
What is BRDC?
Bovine Respiratory Disease Complex
* Shipping fever
* Enzootic pneumonia
What is IBR?
Infectious Bovine Rhinotracheitis
* Common name: Red nose
* Destroys the mucosa, shuts down the muco-ciliary elevator
What is BSRV?
Bovine Syncytial Respiratory Virus
* Can cause respiratory disease on its own: Doesn’t need bacterial help
What are the signs of respiratory disease?
- Cough
- Nasal discharge: White and milky = allergy; Green, brown = infection
- Rapid breathing
- Epistaxis: Bloody nose
When looking at the bovine lung, which is less well oxygenated?
The ventral bovine lung is less well oxygenated than the dorsal lung.
You have more bacterial exposure in the top of the lung (cranial ventral)
- Good indicator of inhaled disease
How long does it take for a bovine lung to complete development?
12 months
What bacteria is involved in Calf Diptheria?
Caused by:
* Fusobacterium necrophorum
* Histophilus somni
Found in the larynx
- Lymphoid tissue is swollen and necortic
What causes Tracheal Stenosis?
- Physical causes; caused by cow pressing down on feeders when eating
- Known as Honker cattle (cattle honk when breathing)
What is interstitial pneumona?
When aveloar walls thicken
Usually caused by a Virus or Toxin
* Aerogenous (viral)
* Hematogenous (toxin)
May see impressions of ribs on lungs
What are signs of BRSV?
- Necrotizing
- Bronchitits/Bronchiolitis
- Syncytial Cells
Suppurative Bronchopneumonia
- See nodules of caseousnecrosis associated with Mycoplasma bovis
- Cold weather disease
- Occurs in the cranial ventral region of the lungs
What are extrapulmonary clues of Mycoplasma bovis?
Otitis media
* Gunk in the ear
* Drainage in the ear
Polyarthritis
* Swelling of the joints
Cottage cheese abcesses
What bacteria cause Fibrinosuppurative Pneumonia?
- Mannheimia haemolytica
- Histophilus somni
- Pasteurella multocida
T/F: Pasteurella is bronchocentric
True
What does the presence of “oat cells” indicate?
Mannheimia haemolytica
What are signs of Histophilus somni?
- Sleepy cows
somni means sleep
