Question of the Day

Mannheimia haemolytica pneumonia typically has a cranioventral distribution – as demonstrated by the hepatized lung (dark red, liver-like) seen in the bottom half of this image. M. haemolytica and Pasteurella multocida are commensals in the upper airway of sheep. Mannheimia haemolytica of sheep and goats is a different strain (type A2) from that in cattle (type A1).

Infection is more likely if there is a primary viral (e.g., parainfluenza-3) or bacterial (e.g., Mycoplasma ovipneumoniae) infection. Pneumonia with these pathogens is most common after recent stress or comingling with new animals. Prevention involves decreasing stress and exposure. There are currently no vaccines available for respiratory disease in sheep and goats and cattle vaccines have not been shown to be effective.

Ovine progressive pneumonia causes chronic wasting with respiratory distress and occasional indurative mastitis.
Necropsy findings include lungs with mottled gray and brown areas of consolidation and very enlarged mediastinal and tracheobronchial lymph nodes.

Corynebacterium pseudotuberculosis causes caseous lymphadenitis in sheep and goats. Multifocal abscesses would be seen on necropsy. Click here to see C. pseudotuberculosis hepatic abscesses.

Dictyocaulus filaria can cause bronchitis or pneumonia in sheep and infection is characterized by tachypnea and coughing.
Hepatization of the lungs would be an uncommon finding at necropsy.

Perilla frutescens causes acute bovine pulmonary emphysema and edema in cattle.

Image courtesy of Lucien Mahin.