Esophagogastric ulcers associated with Ascaris suum infestation in swine.

When a group of 3-month-old pigs was moved to another location, several died from internal bleeding. Two pigs that were necropsied had large esophagogastric ulcers, hepatic fibrosis with "milk spots" and swollen edematous lungs. The ulcers involved the full thickness of the gastric mucosa with pronounced eosinophilic infiltration and perivascular cuffing of the submucosal vessels. There was an acute interstitial and granulomatous pneumonia with an inflammatory exudate composed mainly of eosinophils. Ascarid larvae were recovered from the lungs. Gastric ulceration could have resulted from a second exposure to Ascaris suum infestation because pigs not removed from their original location did not develop ulcers.