Systematic Veterinary Virology

LESIONS

• Birds that die with the peracute disease and young birds may not show significant gross lesions other than severe congestion of the musculature and dehydration.
• In the less acute form, and in mature birds, significant gross lesions are frequently observed, which may consist of subcutaneous edema of the head and neck area, exudation of fluid from nares and oral cavity, congested conjuctiva with petechiation, tracheal lumen filled with excessive mucous exudates, hemorrhagic tracheitis, pinpoint petechial hemorrhages on the keel, very small petechia over the abdominal fat, serosal surfaces, and peritoneum and congestion of kidneys with urate deposition in the tubules.
• In layers, the ovary may be hemorrhagic or degenerated with darkened areas of necrosis and the peritoneal cavity is frequently filled with yolk from ruptured ova, causing severe airsacculitis and peritonitis.
• Hemorrhages may be present on the mucosal surface of the proventriculus — particularly at the juncture with the gizzard. The lining of the gizzard peels easily and frequently reveals hemorrhages and erosions underneath. The intestinal muscosa may have hemorrhagic areas — especially in the lymphoid foci such as the cecal tonsils.
• The lesions in turkeys and domestic ducks are similar to those in chickens but may not be as marked.