Changes

*May cause necrotising [[Bronchi and Bronchioles Inflammatory - Pathology#Infectious causes of bronchitis or bronchiolitis|bronchiolitis]] in immune-deficient foals (Arabian foals)

*May cause necrotising [[Bronchi and Bronchioles Inflammatory - Pathology#Infectious causes of bronchitis or bronchiolitis|bronchiolitis]] in immune-deficient foals (Arabian foals)

*Grossly:

*Grossly:

**[[Lungs - ventilation#Atelectasis (Collapse)|Atelectasis]] and consolidation of lobules in cranioventral region

**[[Lungs Ventilation - Pathology#Atelectasis (Collapse)|Atelectasis]] and consolidation of lobules in cranioventral region

**Mucopurulent exudate in airways

**Mucopurulent exudate in airways

*Histologically:

*Histologically:

*Outbreaks of RSV associated disease usually occur associated with winter housing

*Outbreaks of RSV associated disease usually occur associated with winter housing

*Gross pathology in severe cases  

*Gross pathology in severe cases  

**Cranioventral [[Lungs - ventilation#Atelectasis (Collapse)|atelectasis]] and consolidation

**Cranioventral [[Lungs Ventilation - Pathology#Atelectasis (Collapse)|atelectasis]] and consolidation

**[[Lungs - ventilation#Emphysema|Interstitial emphysema]]  

**[[Lungs Ventilation - Pathology#Emphysema|Interstitial emphysema]]  

***More prominent in the caudal lung lobes

***More prominent in the caudal lung lobes

***Results from bronchoconstriction which results in airway obstruction - this constriction is thought to arise from [[Mast cells - Anatomy & Physiology|mast cell]] degranulation and histamine release

***Results from bronchoconstriction which results in airway obstruction - this constriction is thought to arise from [[Mast cells - Anatomy & Physiology|mast cell]] degranulation and histamine release

*Clinical signs: pyrexia, lethargy, skin erythema, anorexia, severe cough and sneezing, dyspnoea, conjunctivitis, pregnant sows may abort

*Clinical signs: pyrexia, lethargy, skin erythema, anorexia, severe cough and sneezing, dyspnoea, conjunctivitis, pregnant sows may abort

*Grossly:

*Grossly:

**[[Trachea Inflammatory - Pathology|Tracheo]][[Bronchi and Bronchioles Inflammatory - Pathology#Infectious causes of bronchitis or bronchiolitis|bronchitis]], airway obstruction -> [[Lungs - ventilation#Atelectasis (Collapse)|atelectasis]]

**[[Trachea Inflammatory - Pathology|Tracheo]][[Bronchi and Bronchioles Inflammatory - Pathology#Infectious causes of bronchitis or bronchiolitis|bronchitis]], airway obstruction -> [[Lungs Ventilation - Pathology#Atelectasis (Collapse)|atelectasis]]

**[[Pleural Cavity & Membranes Inflammatory - Pathology|Pleura]] normal or covered with serous or serofibrinous exudate

**[[Pleural Cavity & Membranes Inflammatory - Pathology|Pleura]] normal or covered with serous or serofibrinous exudate

**[[Pleural Cavity & Membranes Inflammatory - Pathology|Pleural cavity]] filled with excess fluid

**[[Pleural Cavity & Membranes Inflammatory - Pathology|Pleural cavity]] filled with excess fluid