鸭病毒性肠炎，瘀点和瘀斑出血以及食管白喉膜

Esophageal tissue taken from a duck with duck viral enteritis. The mucosa of the esophagus shows ecchymotic hemorrhages and ulcers in acute cases (left). In more chronic cases (right), the lumen becomes lined with a yellowish-white membrane or, in some cases, the entire mucosa may be sloughed.