Neuroinvasion and neurovirulence
Viruses, including coronavirus, can penetrate the central nervous system (CNS) (neuroinvasion), infect neurons and glial cells (neurotropism), and contribute to, or cause neurological disease (neurovirulence).28 Access may be achieved via two main routes: hematogenous or transneuronal through the olfactory bulb.27,29 On the other hand, the hematogenous route involves directly infecting the blood–brain barrier (BBB) or access via a Trojan such as leukocytes.27,30 Human corona virus strains may infect human monocytes/macrophages,31,32 murine dendritic cells expressing the human aminopeptidase N,33 and human endothelial cells of the BBB.30 As for SARS-CoV-2, detection of the virus in the cerebrospinal fluid of COVID-19 patients has been reported in several publications.26,34