Photomicrographs from a Canada Goose (Branta canadensis) found dead in Wisconsin

Photomicrographs from a Canada Goose (Branta canadensis) found dead in Wisconsin, USA. A) Unaffected esophagus proximal to the impaction showing normal wall layers of the mucosa (M), submucosa (SM), tunica muscularis (TM), and serosa (S), and the presence of submucosal glands (*). B) Esophagus from the area of impaction showing thinning of the mucosa (M) with an area of ulceration (arrow), increased thickness of the submucosa (SM) due to fibrosis and minimal inflammation with loss of the submucosal glands, decreased thickness of the tunica muscularis (TM), and increased thickness of the serosa (S).