Fig. 4: More pronounced histopathologic lesions in the respiratory tract with Bovine and Human H5N1s compared to Mountain Lion isolate.

A Hamsters (n = 4 per group) were inoculated with Bovine, Mountain Lion, or Human H5N1 viruses, and tissues were collected at 4 dpi. Representative images of hematoxylin and eosin-stained (H&E) and immunohistochemistry (IHC) of Nasal turbinates (NT), trachea, and lung tissues at 4 dpi. Influenza A virus antigen was detected by IHC targeting influenza A virus nucleoprotein. Magnification and scale bars: NT: 400×, bar = 20 µm, Trachea: 200×, bar = 50 µm, and Lungs: 200×, bar = 50 µm. B–D Semi quantitative pathological scoring of NT (B), trachea (C), and lungs (D). E Cumulative scoring of the presence of viral antigen in the respiratory tissues based on IHC staining. Statistical significance for panels (B–E) was assessed using the Kruskal-Wallis test. For graphs (B–E) data are represented as box-and-whisker plots depicting the median (center line) and interquartile range (25th–75th percentiles). Whiskers indicate minimum and maximum values and all individual data points are shown.