Changes

*Caused by [[Orthomyxoviridae]]

*Caused by [[Orthomyxoviridae]]

*[[Rhinitis|Rhinitis]], may progress to [[Lungs Inflammatory - Pathology#Infectious causes of pneumonia|pneumonia]]

*[[Rhinitis|Rhinitis]], may progress to [[Pneumonia Overview#Infectious causes of pneumonia|pneumonia]]

*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:

**Lung lesions  

**Lung lesions  

***Clear demarcation of lesions in cranial and middle lobes  

***Clear demarcation of lesions in cranial and middle lobes  

***[[Lungs Inflammatory - Pathology#Interstitial pneumonia|Interstitial pneumonia]]

***[[Interstitial Pneumonia|Interstitial pneumonia]]

*Histologically:

*Histologically:

**Acute inflammation of mucosa of trachea and bronchi

**Acute inflammation of mucosa of trachea and bronchi