Changes

*Clinical disease most severe in young calves - can develop mucosal ulcerative lesions in the [[Oesophagus#Erosive & Ulcerative Pathology|oesophagus]] and forestomachs and viraemia with multiorgan infection

*Clinical disease most severe in young calves - can develop mucosal ulcerative lesions in the [[Oesophagus#Erosive & Ulcerative Pathology|oesophagus]] and forestomachs and viraemia with multiorgan infection

*Cause of abortion >5 months of gestation

*Cause of abortion >5 months of gestation

*May contribute to [[Bacterial infections#Enzootic pneumonia of calves|Enzootic pneumonia of calves]]

*May contribute to [[Respiratory Bacterial Infections - Pathology#Enzootic pneumonia of calves|Enzootic pneumonia of calves]]

*Causative agent: [[Paramyxoviridae#Bovine Parainfluenza - 3 (PI-3)|parainfluenza- 3 virus]] (PI3)

*Causative agent: [[Paramyxoviridae#Bovine Parainfluenza - 3 (PI-3)|parainfluenza- 3 virus]] (PI3)

*On its own causes [[Nasal cavity - inflammatory#Infectious causes of rhinitis|rhinitis]]  

*On its own causes [[Nasal cavity - inflammatory#Infectious causes of rhinitis|rhinitis]]  

*Often part of multi-aetiology disease complex (e.g. [[Bacterial infections#Enzootic pneumonia of calves|Enzootic pneumonia of calves]]), often followed by [[Pasteurella species and Mannheimia haemolytica|''Pasteurella sp.'']] obscuring viral origin

*Often part of multi-aetiology disease complex (e.g. [[Respiratory Bacterial Infections - Pathology#Enzootic pneumonia of calves|Enzootic pneumonia of calves]]), often followed by [[Pasteurella species and Mannheimia haemolytica|''Pasteurella sp.'']] obscuring viral origin

*Replicates in airway epithelial cells and results in an initial [[Bronchi and bronchioles - inflammatory#Infectious causes of bronchitis or bronchiolitis|bronchitis -> bronchiolitis]] -> extension into [[Lungs - inflammatory#Infectious causes of pneumonia|alveoli]], causing [[Lungs - inflammatory#Bronchointerstitial pneumonia|bronchointerstitial pneumonia]]  

*Replicates in airway epithelial cells and results in an initial [[Bronchi and bronchioles - inflammatory#Infectious causes of bronchitis or bronchiolitis|bronchitis -> bronchiolitis]] -> extension into [[Lungs - inflammatory#Infectious causes of pneumonia|alveoli]], causing [[Lungs - inflammatory#Bronchointerstitial pneumonia|bronchointerstitial pneumonia]]  

*Early stages may show [[General Pathology - Degenerations and Infiltrations#Cellular Inclusions|intracytoplasmic inclusions]]

*Early stages may show [[General Pathology - Degenerations and Infiltrations#Cellular Inclusions|intracytoplasmic inclusions]]

*Causative agent: [[Adenoviridae|bovine adenovirus]]

*Causative agent: [[Adenoviridae|bovine adenovirus]]

*[[Nasal cavity - inflammatory#Infectious causes of rhinitis|Rhinitis]]

*[[Nasal cavity - inflammatory#Infectious causes of rhinitis|Rhinitis]]

*May contribute to [[Bacterial infections#Enzootic pneumonia of calves|Enzootic pneumonia of calves]]

*May contribute to [[Respiratory Bacterial Infections - Pathology#Enzootic pneumonia of calves|Enzootic pneumonia of calves]]

**[[Bronchi and bronchioles - inflammatory#Acute bronchitis/bronchiolitis|Acute bronchiolitis]], characteristic of the bronchiolar response is the formation of syncytial giant cells  (formed by proliferating bronchiolar epithelial cells which may contain [[General Pathology - Degenerations and Infiltrations#Cellular Inclusions|intracytoplasmic inclusion bodies]]), alveolar epithelium sometimes affected

**[[Bronchi and bronchioles - inflammatory#Acute bronchitis/bronchiolitis|Acute bronchiolitis]], characteristic of the bronchiolar response is the formation of syncytial giant cells  (formed by proliferating bronchiolar epithelial cells which may contain [[General Pathology - Degenerations and Infiltrations#Cellular Inclusions|intracytoplasmic inclusion bodies]]), alveolar epithelium sometimes affected

**Obstruction of bronchioles by exudate - these may later become obliterated by the fibrous tissue of organisation

**Obstruction of bronchioles by exudate - these may later become obliterated by the fibrous tissue of organisation

*May contribute to [[Bacterial infections#Enzootic pneumonia of calves|Enzootic pneumonia of calves]]

*May contribute to [[Respiratory Bacterial Infections - Pathology#Enzootic pneumonia of calves|Enzootic pneumonia of calves]]

===Bovine rhinovirus===

===Bovine rhinovirus===