Unraveling the Possible Routes of SARS-COV-2 Invasion into the Central Nervous System

Lima, Maria; Siokas, Vasileios; Aloizou, Athina-Maria; Liampas, Ioannis; Mentis, Alexios-Fotios A.; Tsouris, Zisis; Papadimitriou, Anastasios; Mitsias, Panayiotis D.; Tsatsakis, Aristidis; Bogdanos, Dimitrios P.; Baloyannis, Stavros J.; Dardiotis, Efthimios

PURPOSE OF REVIEW: To describe the possible neuroinvasion pathways of Severe Acute Respiratory Syndrome-related Coronavirus-2 (SARS-CoV-2), the virus responsible for the Coronavirus disease-19 (Covid-19) pandemic. RECENT FINDINGS: We present data regarding the family of Coronaviruses (CoVs) and the central nervous system (CNS), and describe parallels between SARS-CoV-2 and other members of the family, which have been investigated in more depth and combine these findings with the recent advancements regarding SARS-CoV-2. SUMMARY: SARS-CoV-2 like other CoVs is neuroinvasive, neurotropic and neurovirulent. Two main pathways of CNS penetration seem to be the strongest candidates, the hematogenous and the neuronal. Τhe olfactory route in particular appears to play a significant role in neuroinvasion of coronaviruses and SARS-CoV-2, as well. However, existing data suggest that other routes, involving the nasal epithelium in general, lymphatic tissue and the CSF may also play roles in SARS-CoV-2 invasion into the CNS.