Fig. 2.

Neural invasion of SARS-CoV-2 can occur via olfactory epithelium, enteric inhibitory neurons, or hematogenous spread after breaching the blood brain barrier. Both ACE2 and cell entry protease (TMPRSS2) aid in viral entry and are expressed in cells including olfactory epithelium, myelin-forming cells, enteric inhibitory neurons, and vascular endothelium. Therefore, enteric neural synaptic junctions containing ACE2 and related proteases may support retrograde spread of SARS-CoV-2 in the central nervous system and contribute to central neurogenic disorders observed in COVID-19 infection