Figure 1. Brain and tonsil sections from a CWD-infected mule deer, immunolabelled for PrP. (a) Brain section at the level of the obex shows the dorsal motor nucleus of the vagus extensively labelled for PrP in the neuropil, however neuronal cell bodies are unstained. (b) Perivascular labelling in the obex is commonly seen in CWD-infected deer. (c) White matter tracts are labelled for PrP (d) Tonsil contains PrP immunoreactivity within the lymphoid follicles. Uninfected deer show no PrP immunolabelling in brain or tonsils (data not shown). (A colour version of this figure is available at www.edpsciences.org/vetres.).