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PI3
Pathogenesis
- Virulence varies with isolates
- Cessation of ciliary clearance and epithelial necrosis predisposes to secondary bacterial infections -> cough
- May cause rhinitis of cattle
Diagnosis
- Diseased lung tissue from dead animals or centrifuged cells from lung lavage
- Virus is too fragile for cell culture isolation (often inactivated in transport)
- Antigen detection by immunocytochemistry for intracytoplasmic viral inclusions containing labelled viral protein
- Serology: 4-fold rise in ELISA antibody in paired serum samples from several animals
Control
- Improve managemental factors
- All-in, all-out systems
- Some vaccination
- Temperature sensitive mutant that replicates at 34oC but not at 37oC
- Re-infection is common
Secondary Concerns
- With other agents causes calf pneumonia
- Associated with poor management:
- Overcrowding
- Poor ventilation
- High humidity
- Deprivation of colostrum
- Stress caused by transport or mixing of stock