Figure 4.

Summary of the anatomical localization, cell type, and viral protein spread observed in SARS-CoV-2-infected monkeys

Schematic representation of the components of the olfactory circuit theorized to serve as the SARS-CoV-2-spreading pathway during the acute stage of the disease. The major viral proteins analyzed in this study were contained within the neural circuitry of the primary olfactory cortex, extending to the medial part of the OFC, a secondary olfactory region, only in aged monkeys. A robust immune response characterized by systemic neutrophil recruitment associated with disrupted blood vessels and local microglia and astrocyte activation was observed across all regions analyzed, including part of the hippocampal formation. I, cortical layer I; II, cortical layer II; III, cortical layer III; IV, cortical layer IV; V, cortical layer V; VI, cortical layer VI; ACE2, angiotensin-converting enzyme 2; dsRNA, double-stranded RNA; HF-CA1, hippocampal formation, CA1 field; mOFC, orbitofrontal cortex, medial part; OT, olfactory tubercle; PC, piriform cortex; rEC, entorhinal cortex, rostral subdivision; Sub, subicular complex.