FIG 7.

Gross pathology and histopathology of lungs from pigs infected with three representative P9-derived viruses. Lungs were isolated from pigs directly infected with the L2, N9, L18, and control parental rH1N1 viruses at 6 dpi or as in-contacts at 8 dpi (7 dpc). (A to C) Lungs from directly infected L2, N9, and L18 viruses showed moderate pulmonary consolidation (white arrows) and moderate to severe bronchopneumonia with interstitial pulmonary edema and inflammatory cell infiltrates in alveolar space. (E to G) Lungs from in-contact pigs exposed to L2, N9, and L18 viruses also showed mild lung consolidation (white arrows) and mild to moderate bronchopneumonia. (D and H) There was no apparent pathological damage detected in lungs of rH1N1-infected and in-contact pigs. Images shown are representative of three pigs from three independent experiments. Scale bar, 200 μm.