Figure 1. Gross and microscopic lesions from dog infected with highly pathogenic avian influenza (HPAI) H5N1. A) Severe congestion and edema in the lung. B) Lung histopathologic results showing severe pulmonary edema and hemorrhage with black-brown particles (hemosiderin) (magnification ×100). C) Liver histopathologic changes showing necrotic foci (pale area) (magnification ×100). D) Immunohistochemical results: the nucleoprotein of the virus is detected in nuclei of hepatocytes with brown granule (magnification ×200).