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Volume 32, Number 8—August 2026
Research
Detection of Highly Pathogenic Avian Influenza A(H5N1) Clade 2.3.4.4b Genotype D1.2 Virus in Swine after Experimental Inoculation
Figure 5
![Distribution of influenza A virus nucleoprotein (NP) antigen across multiple body systems in a study of systemic distribution and protracted detection of highly pathogenic avian influenza A(H5N1) clade 2.3.4.4b genotype D1.2 virus in swine after experimental inoculation. NP antigen (brown) was detected at 5 days postinoculation in the neurons (arrowhead) and associated axons (arrows) of the olfactory bulb in the absence of notable lesions (panel A; animal no. 641; original magnification ×400), skeletal myocytes and an adjacent axon (arrowhead) (panel B; animal no. 645; original magnification ×40 and ×400 [inset]), the Peyer’s patch of the ileum in cell morphologies consistent with antigen-presenting leukocytes (arrowhead) and lymphocytes (arrow) (panel C; animal no. 641; original magnification ×100 and ×400 [inset]), and rarely in the lamina propria of the ileum (panel D; animal no. 641; original magnification ×400) and mesenteric lymph node attached to the spiral colon (panel E; animal no. 641; original magnification ×400).](/eid/images/25-1765-F5.jpg)
Figure 5. Distribution of influenza A virus nucleoprotein (NP) antigen across multiple body systems in a study of systemic distribution and protracted detection of highly pathogenic avian influenza A(H5N1) clade 2.3.4.4b genotype D1.2 virus in swine after experimental inoculation. NP antigen (brown) was detected at 5 days postinoculation in the neurons (arrowhead) and associated axons (arrows) of the olfactory bulb in the absence of notable lesions (panel A; animal no. 641; original magnification ×400), skeletal myocytes and an adjacent axon (arrowhead) (panel B; animal no. 645; original magnification ×40 and ×400 [inset]), the Peyer’s patch of the ileum in cell morphologies consistent with antigen-presenting leukocytes (arrowhead) and lymphocytes (arrow) (panel C; animal no. 641; original magnification ×100 and ×400 [inset]), and rarely in the lamina propria of the ileum (panel D; animal no. 641; original magnification ×400) and mesenteric lymph node attached to the spiral colon (panel E; animal no. 641; original magnification ×400).