Figure 4. Brain of bank vole at 133 dpi.

A. Marked focal, predominantly mononuclear leptmeningitis (arrows), surrounding a medium-sized artery that exhibits focal extensive fibrinoid necrosis of the wall (*) and focal degenerative changes of endothelial cells (arrowheads). HE stain; Bar = 20 µm. B. TBEV antigen is expressed cell free and by macrophages (arrows) and occasionally also by neutrophils (inset: arrowhead) in the infiltrate. Horseradish peroxidase method, Papanicolaou's hematoxylin counterstain; Bar = 20 µm (inset: 10 µm).