Changes

*Early stages (only first few days) may show [[Degenerations and Infiltrations - Pathology#Cellular Inclusions|intracellular inclusions]] in the respiratory mucosal epithelial cells

*Early stages (only first few days) may show [[Degenerations and Infiltrations - Pathology#Cellular Inclusions|intracellular inclusions]] in the respiratory mucosal epithelial cells

*Leading to neutrophilic inflammation of varying severity.... serous -> catarrhal -> purulent  

*Leading to neutrophilic inflammation of varying severity.... serous -> catarrhal -> purulent  

*With secondary bacterial infection (eg: [[Pasteurella species and Mannheimia haemolytica|Pasturella spp.]], [[Mycoplasmas|Mycoplasma spp.]], [[Fusobacterium|Fusobacterium necrophorum]]) can lead to fibrinous to necrotizing inflammation; mucosal sloughing, ulceration... pyrexia, dyspnoea ... [[Lungs Inflammatory - Pathology#Aspiration pneumonia|inhalation pneumonia]]... death

*With secondary bacterial infection (eg: [[Pasteurella species and Mannheimia haemolytica|Pasturella spp.]], [[:Category:Mycoplasmas|Mycoplasma spp.]], [[Fusobacterium|Fusobacterium necrophorum]]) can lead to fibrinous to necrotizing inflammation; mucosal sloughing, ulceration... pyrexia, dyspnoea ... [[Lungs Inflammatory - Pathology#Aspiration pneumonia|inhalation pneumonia]]... death

*Underlying hyperaemic inflammatory response

*Underlying hyperaemic inflammatory response

*Can become latent following primary infection

*Can become latent following primary infection