Fig. 1.

Demonstration of neurotropism. Coronavirus in the nasal cavity can directly cross the transcribrial opening in the ethmoid bone to access the brain or perform (a) transsynaptic retrograde migration using the vesicle transport machinery used by neurotransmitters. (b) In blood circulation, the virus can infect vascular endothelial cells, which further provide access to the glial cells of CNS; alternatively, virally infected leukocytes can transport the virus across the BBB and facilitate the infection of the CNS