Fig 2. Haematoxylin and eosin staining of 5 micron thick sections from two affected and two unaffected calves at 40x magnification.

(a) Thalamus of calf 2 showing nuclei with foamy, granular basophilic cytoplasm (black arrow), degenerate neurons with a condensed and basophilic nucleus (orange arrow) with the ensuing phagocytosis (red arrows) and macrophages with brown-pigmented cellular debris accumulating around a blood vessel (green arrow). (b) Cerebellar white matter of calf 3 showcasing widespread foamy vacuolation of the cytoplasm of neurons and glia, with eosinophilic and axonal swellings (white arrows) and macrophages and lymphocytes surrounding a small blood vessel (grey arrow). (c) Thalamus from a healthy calf and (d) cerebellum from a healthy calf.