Brain of bank voles at 12 and 14 dpi.

<p>A, B. Animal euthanized at 12(arrow) and microglial activation. HE stain; Bar = 10 µm. B. Staining for TBEV antigen. Cerebellum with Purkinje cell expressing viral antigen in the cell body (arrows) and in cell processes (arrowheads). Inset: Viral antigen expression in cell body and processes (arrowheads) of an individual neuron surrounded by microglial cells/macrophages (satellitosis). Horseradish peroxidase method, Papanicolaou's hematoxylin counterstain; Bars = 10 µm. C–E. Cerebellum of animal scheduled sacrificed at 14 dpi. C. Satellitosis around Purkinje cells (arrows). HE stain; Bar = 10 µm. D. Purkinje cells expressing viral antigen, surrounded by microglial cells/macrophages (satellitosis). Horseradish peroxidase method, Papanicolaou's hematoxylin counterstain; Bar = 10 µm. E. Mild focal astrogliosis in area with increased cellularity (arrow: microglial nodule/infiltrating macrophages), indicated by the presence of GFAP-positive star-shaped reactive astrocytes (arrowheads) with numerous long processes. Peroxidase anti-peroxidase method, Papanicolaou's hematoxylin counterstain; Bar = 10 µm.