Resp2- BRD Complex

  1. What are the 3 major factors that play into development of BRD (or any respiratory disease for that matter)?
    environmental stresses--> viral infection--> bacterial infection
  2. How does stress predispose animals to viral infection?
    stress--> increased cortisol--> cortisol is an immunosuppressant
  3. What are the 2 major mechanisms of viral infection associated with shipping fever?
    epithelial damage (cytolytic epithelial cell death, loss of cilia, change in surfactant--> decreased function of mucociliary elevator), immunomodulation (reduced function of neuts and macs and adaptive immunity)
  4. What is the most important aspect of pathogenesis of BRD complex that leads to severe morbidity and death?
    virus infection to predispose to secondary bacterial infection
  5. What are the major primary viral agents associated with BRD complex? (6)
    bovine herpesvirus-1, parainfluenza-3, BRSV, BVDv, bovine adenovirus, bovine coronavirus
  6. What are the gross lesions associated with uncomplicated bovine viral pneumonia? (3)
    diffusely non-collapsing, rubbery to firm lungs (bronchointerstitial or interstitial pneumonia), interstitial edema and/or emphysema, rhinitis and tracheitis (only if BHV-1)
  7. How does secondary bacterial pneumonia arise with BRD complex?
    viral pneumonia lowers defenses--> commensal bacteria of airways shift to pathogenicity as opportunistic pathogens--> high morbidity and mortality
  8. What are the major secondary bacterial agents associated with BRD complex? (6)
    Mannheimia haemolytica, Pasteurella multocida, Histophilus somni, Mycoplasma bovis, Truperella pyogenes, Bibersteinia trehalosi
  9. What bacteria have LPS (3), and what are the consequences of LPS in the body? (2)
    M. haemolytica, P. multocida, B. trehalosi; LPS induces endothelial damage (endotoxemia) and is proinflammatory
  10. What bacteria have lipooligosaccharide (1), and what are its effects in the body? (2)
    H. somni; endothelial damage and proinflammatory [ sidenote: H. somni causes emboli and hemorrhages in the brain]
  11. What bacteria have leukotoxin (2), and what are its effects in the body? (2)
    M. haemolytica and +/- B. trehalosi; causes inflammatory cell necrosis and apoptosis
  12. What are gross lesions associated with secondary bacterial infection of the lungs with BRD complex? (4)
    cranioventral distribution; firm, dark red to tan parenchyma +/- exudate; pleural effusion and fibrin indicative of M. haemolytica and H. somni
  13. What is a critical point of intervention for controlling BRD complex in calves?
    modulating stress
Card Set
Resp2- BRD Complex
vetmed resp2