Table 2.

CNS Pathology and Summary of Findings.

ID	Route of infection	Age (years)	Sex	CNS pathology and summary of findings
RM1	Multi-route mucosal	14.01	Male	Multiple acute microhemorrhages (++++) were observed in cerebellum, BG, and brainstem. Marked neuronal and surrounding cell injury was seen within cerebellum and brainstem. Cleaved caspase 3 positivity was mostly limited to Purkinje cells and immediate neighbors (+++) in cerebellum. BG had a single region of cell with sporadic caspase 3 positivity within the area. Limited vascular caspase 3 positivity was also observed in the BG (+). No caspase 3 positivity was observed in brainstem despite large regions with abnormal neuronal morphology. Limited SARS-N positivity was found in endothelium of cerebellum, brainstem, and BG (+).
RM2	Multi-route mucosal	12.97	Female	Acute microhemorrhages were seen in cerebellum and BG (+). Marked neuronal injury was present in cerebellum and brainstem. Cleaved caspase 3 positivity was observed in Purkinje cells and immediate neighbors in cerebellum and parenchymal cells in brainstem (+++). Rare caspase 3 positivity was observed in cerebellar endothelium, with much greater EC positivity seen in brainstem (+++). Caspase 3 was also observed in BG endothelium, but to a lesser degree (+). BG also showed limited caspase 3 positivity of parenchymal cells with apparent nuclear dissolution and surface blebs (+). Parietal lobe showed rare cleaved caspase 3 positivity in ECs and parenchymal cells. This was localized to blood vessels within associated areas of tissue damage that contained cells at different stages of nuclear dissolution with apparent blebbing. The temporal lobe had several foci with high cleaved caspase 3 positivity (+++). Cleaved caspase 3 was also seen with moderate frequency in temporal lobe ECs (++). Limited SARS-N positivity in endothelium of cerebellum and brainstem (+), with infrequent positivity observed in BG.
RM3	Aerosol	13.06	Male	An acute microhemorrhage was seen in the BG but not in cerebellum or brainstem, in contrast to the majority of our study animals. Moderate neuronal injury with vacuoles in WM were seen in cerebellum. Rare cleaved caspase 3 positivity was seen in Purkinje cells and immediate neighbors. Limited pyknotic neurons were observed in brainstem, however, infrequent caspase 3 positivity was restricted to the endothelium. Rare cleaved caspase 3 positivity was also observed in parietal lobe, despite apparent areas of cell injury/death. Rare SARS-N positivity was detected in endothelium of brainstem, BG, and parietal and temporal lobes.
RM4	Aerosol	15.03	Male	A moderate number of acute microhemorrhages (++) were seen in cerebellum, BG, and brainstem. Marked neuronal injury was observed in cerebellum with WM vacuolation. Active caspase 3 positivity was not detected. In brainstem, foci of cell injury/apoptosis were seen with active caspase 3 positivity in parenchymal cells and endothelium (++). Rare SARS-N positivity was found in endothelium of cerebellum and temporal lobe, with infrequent positivity in parietal and occipital lobes.
RM5	(mock) Multi-route mucosal	17.97	Female	Acute areas of neuronal injury in the Purkinje cell layer of the cerebellum (+). No microhemorrhages were seen in any regions. All brain regions were negative for cleaved caspase 3 and SARS nucleocapsid.
RM6	(mock) Multi-route mucosal	21.62	Male	Healthy brain morphology was generally observed. A microhemorrhage was noted in the brainstem, basal ganglia, and cerebellum. All brain regions were negative for cleaved caspase 3 and SARS nucleocapsid.
AGM1	Aerosol	16.28	Female	Extensive acute microhemorrhages (++++) were seen in cerebellum, BG, and brainstem. Marked neuronal and neighboring cell injury were also seen in cerebellum, BG, and brainstem but without cleaved caspase 3 positivity. Likewise, cleaved caspase 3 was not seen in parietal lobe, despite obvious cell/tissue injury and/or death. Rare SARS-N positivity was detected in endothelium of cerebellum, brainstem, and BG, which was infrequent and dim in the temporal lobe.
AGM2	Multi-route mucosal	16.29	Female	A considerable number of acute microhemorrhages (++++) were observed in cerebellum, BG, and brainstem. While marked neuronal injury was observed in cerebellum, cleaved caspase 3 positivity in Purkinje cells and immediate neighbors was moderate (++). Brainstem had foci of caspase 3 positivity (++), whereas the parietal lobe contained regions of apparent cell injury/death without cleaved caspase 3 positivity. Rare SARS-N positivity was noted in endothelium of cerebellum, brainstem, BG, and parietal lobe.
AGM3	Multi-route mucosal	16.3	Male	Several acute microhemorrhages (+++) were seen in cerebellum, BG, and brainstem. Marked neuronal caspase 3 positivity was seen in Purkinje cells and immediate neighboring cells (+++) within the cerebellum, whereas EC-associated positivity was rare. Considerable caspase 3 positivity was present in parenchymal and ECs of brainstem (++++) and parietal lobe [parenchymal (+++); ECs (+)]. Rare SARS-N positivity was observed in the endothelium of cerebellum, brainstem, BG, and temporal lobe.
AGM4	Aerosol	16.33	Male	Several acute microhemorrhages (+++) were seen in cerebellum and brainstem. Cerebellum showed marked neuronal injury with moderate cleaved caspase 3 positivity in Purkinje cells and immediate neighbors (++). Rare caspase 3 positivity was seen in cerebellar and BG endothelial cells. Focal regions of parenchymal cell injury were present in brainstem with active caspase 3 positivity in parenchymal cells and ECs (+). A single region within the parietal lobe had considerable cleaved caspase 3 positivity in the parenchyma (++++ for this area only). Limited SARS-N positivity was seen in endothelium of cerebellum, brainstem, and BG (+), which was infrequent in temporal, parietal, and occipital lobe endothelium.
AGM5	(mock) Multi-route mucosal	17.34	Female	Several microhemorrhages seen in the cerebellar white matter and granular layer (+). Rare cleaved caspase 3 positivity in the frontal lobe. All brain regions were negative for SARS nucleocapsid.
AGM6	(mock) Multi-route mucosal	17.34	Male	Microhemorrhages were noted in the basal ganglia, brainstem, and cerebellum with larger bleeds in the white matter (+). Rare vacuoles in cerebellum (+). Sparse cleaved caspase 3 positivity in the cerebellum, basal ganglia, and brainstem but not near the areas of microhemorrhages. All investigated brain regions were negative for SARS nucleocapsid.

A within laboratory scoring scale, ranging from limited (+), mild (++), moderate (+++), and severe (++++) indicates the degree of positivity of specific antigens investigated or severity of observed pathology.

BG basal ganglia, WM white matter, ECs endothelial cells, RM Rhesus macaque, AGM African green monkey.