1) Intestine of diseased pig having heavy red color extended even on serous membrane.
2) Mucous membrane of the jejunum turns to dark red color due to severe hyperemia or hemorrhage, having bloody contents.
3) Profused necrosis of epithelial cells of mucous membrane of the small intestine (HE staining).
4) Enlargement of No.3. Necrosis and hemorrhage of epithelial cells and proper mucosa and marked cell infiltration at under part of proper mucous membrane.