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Volume 32, Number 5—May 2026
Dispatch
Tropism and Replication Competence of Cattle Influenza A(H5N1) Genotype B3.13 Virus in Human Bronchus and Lung Tissue
Figure 2

Figure 2. Immunohistochemical stain of nucleoprotein from samples in a study of tropism and replication competence of cattle influenza A(H5N1) genotype B3.13 virus in human bronchus and lung tissue. Formalin-fixed, paraffin-embedded sections of human bronchus (A) and lung (B) tissue explants at 48 hours postinfection are shown. Cells positive for influenza A nucleoprotein are indicated by red-brown color. Green arrows indicate ciliated cells; yellow arrows indicate nonciliated cells. Images are representatives of 3 separate donors. Cattle influenza A(H5N1) genotype B.13 virus strains A/dairy_cow/Ohio/B24OSU-439/2024 (H5N1/439) and A/dairy_cow/Texas/98638/2024 (H5N1/98638) are compared with historical human isolates of highly pathogenic avian influenza strains H5N1/483, H5N6/39715, and H1N1pdm/415742 (Appendix Tables 1, 2). Scale bars indicate 100 μm.