Immunohistochemical staining of avian influenza virus antigens in lung tissue from a pig. Immunohistochemical detection of avian influenza virus (AIV) antigens in lung section from AIV infected pig euthanized PID 4, using goat anti-influenza A antibody and counterstaining with hematoxylin. AIV antigen positive (red) epithelial cells are seen in the alveolar septa (arrows). The area is partly consolidated. (Original magnification x20).
Trebbien et al. Virology Journal 2011 8:434 doi:10.1186/1743-422X-8-434