Schematic depiction of anatomical organization of mouse brain in medial sagittal view.

AON: anterior olfactory nucleus, BF: basal forebrain, CC: cerebral cortex (isocortex), CP: caudate putamen, F: fornix, HIP: hippocampus, OB: olfactory bulb, VS: ventral striatum. Progress of infection with WEEV after intranasal inoculation (A–D). Whole heads were bisected along sagittal midline and imaged at 24 hpi (A), 48 hpi (B), 60 hpi (C) and 72 hpi (D). Luciferase activity pattern is consistent with dissemination along olfactory pathways. Regions consistent with initial infection of the nasal turbinates show pronounced FLUC activity at 24 hpi. However, nasal turbinate BLM activity is exceeded by signal from areas consistent with infection proceeding through olfactory information processing within the CNS, including the lateral olfactory tract, anterior olfactory nucleus, basal ganglia, thalamus, and cerebrum. Immunological markers of disease (MCP-1 and IP-10), resulting from WEEV.MCM.FLUC, are strongly induced and comparable to WEEV.McM at 3 d.p.i. (E–F).