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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

Hannah Seger, Amy L. Baker, Alexandra C. Buckley, Tavis K. Anderson, Alexey Markin, Alessandra Campos, Bruno Caetano Trindade, Marissa Vincent, Giovana Ciacci Zanella, Mia Torchetti, Kristina Lantz, and Bailey ArrudaComments to Author 
Author affiliation: Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee, USA (H. Seger); US Department of Agriculture Agricultural Research Service National Animal Disease Center, Ames, Iowa, USA (H. Seger, A.L. Baker, A.C. Buckley, T.K. Anderson, A. Markin, A. Campos, B.C. Trindade, M. Vincent, G.C. Zanella, B. Arruda); Iowa State University College of Veterinary Medicine, Ames (G.C. Zanella); US Department of Agriculture Animal and Plant Health Inspection Service National Veterinary Services Laboratories, Ames (M. Torchetti, K. Lantz)

Main Article

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).

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).

Main Article

Page created: June 23, 2026
Page updated: July 27, 2026
Page reviewed: July 27, 2026
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