Figures 1–6.

Encephalitis in bovine astrovirus (BoAstV)-positive cattle. Figure 1. Perivascular cuff of leukocytes. H&E. Bar = 20 μm. Figure 2. Perivascular cuff of leukocytes near a glial nodule (arrow), in the region of the thalamus and basal nuclei. H&E. Bar = 50 μm. Figure 3. Higher magnification of Fig. 2; a glial nodule with neuronophagia (arrow). H&E. Bar = 10 μm. Figure 4. Necrotic neuron with pyknotic nucleus and shrunken, angular, hypereosinophilic cytoplasm (arrow), and gliosis of the neuroparenchyma. H&E. Bar = 20 μm. Figure 5. CD3-immunoreactive T lymphocytes in a perivascular cuff and in a glial nodule, with scattered CD3-positive T cells in the adjacent neuroparenchyma. Midbrain. Immunohistochemistry (IHC) for CD3. Bar = 50 μm. Figure 6. A glial nodule contains Iba1-immunoreactive macrophages. Dispersed Iba1-positive cells in the surrounding neuroparenchyma are consistent with microglia. Cerebrum. IHC for Iba1. Bar = 100 μm.