Systematic Veterinary Virology

LEISONS

• In peracute form the most characteristic changes are edema of the lungs or hydrothorax. In very peracute cases, extensive alveolar edema and mottled hyperemia of the lungs are seen. Other less commonly observed lesions are periaortic and peritracheal edematous infiltration, diffuse or patchy hyperemia of the glandular fundus of the stomach, hyperemia and petechial hemorrhages in the mucosa and serosa of the small and large intestines. Most of the lymph nodes are enlarged and edematous, especially those in the thoracic and abdominal cavities.
• In cardiac form the prominent lesion is a yellow gelatinous infiltration in the subcutaneous and intermuscular fascia primarily of the head, neck, and shoulders. Extensive petechial and ecchymotic hemorrhages on the epicardium and endocardium, particularly of the left ventricle are also observed. 
• In mixed form the lesions represent a combination of those found in the pulmonary and cardiac forms