Figure 1: Histopathologic features in lungs and trachea of mice experimentally infected with AI H11N1 virus. A. Lung, H11N1-infected mice: Focal non-coalescent small areas of consolidation, mild intra-alveolar, intrabronchiolar, intraseptal, and interstitial mononuclear cell (MNC) inflammatory infiltrate. Peribronchiolar and perivascular cuff of mild MNC infiltrate was also evident. B. Trachea, H11N1-infected mice: Trachea showed mild MNC infiltrate in submucosa with intact mucosa and scant inflammatory exudates in the lumen. C. Lung, un-infected mouse: Normal histology. D. Trachea, un-infected mouse: Normal histology. All sections are H-E stained, original magnifications, A-D: 200X.