The coronavirus is able to penetrate directly into the olfactory bulb, therefore it is able to reach the nervous system; this explains the reason for the loss of smell. This is what emerges from the clinical cases reported by Patrizia Morbini of the University of Pavia reported in the journal JAMA Otolaryngology - Head & Neck Surgery. "We were able to take the olfactory bulb in only two patients - says the expert in an interview with ANSA - and the study reports the results observed in one of the two, who had a severe form of COVID".
"In this patient - continues the expert - we demonstrated with electron microscopy the presence of the virus in the olfactory bulb; associated with severe inflammation". This aspect suggests direct damage of the virus in the olfactory bulb. However, it was not possible to establish precisely in which cell types the viral particles were present.
Furthermore, "as regards the nose and in particular the olfactory mucosa, which we specifically isolated - Morbini specifies - here too we observed the presence of abundant viral particles, associated with inflammation, in both patients studied". Although this is a case report, therefore a single clinical observation, Morbini concludes, "ours represents the first evidence of a direct involvement of the olfactory bulb by SARS-CoV-2, which supports the instrumental damage data in this area in COVID patients, and clinical evidence of impaired smell. This suggests that this virus, like other coronaviruses, is able to reach the nervous system via olfactory mucosal receptor fibers. "