Figure 5. Pathologic findings from a patient (number 6) with confirmed influenza A (H5N1) infection. All slides are stained with hematoxylin and eosin, shown at 40x objective. Panel A shows hyaline membrane formation lining the alveolar spaces of the lung and vascular congestion with a few infiltrating lymphocytes in the interstitial areas. Reactive fibroblasts are also present. Panel B is an area of lung with proliferating reactive fibroblasts within the interstitial areas. Few lymphocytes are seen, and no viral intranuclear inclusions are visible. Panel C shows fibrinous exudates filling the alveolar spaces, with organizing formation and few hyaline membranes. The surrounding alveolar spaces contain hemorrhage. Panel D is from a section of spleen, showing numerous atypical lymphoid cells scattered around the white pulp. No viral intranuclear inclusions are seen.