RIO DE JANEIRO, BRAZIL – Researchers from the University of São Paulo Medical School (FM-USP) have found that SARS-CoV-2 infects and replicates in salivary gland cells. The study’s findings, supported by FAPESP, have been published in the Journal of Pathology.
Through the analysis of samples from 3 types of salivary glands collected during a minimally invasive autopsy procedure in patients who died from Covid-19 complications at the FM-USP Hospital, they found that these tissues, which produce and secrete saliva, are reservoirs for the novel coronavirus.
The findings help explain why the novel coronavirus is found in large amounts in saliva, which made testing for Covid-19 diagnoses based on the fluid feasible, the study’s authors emphasize.
“This is the first report of a respiratory virus capable of infecting and replicating in salivary glands. Until now, it was believed that only viruses causing very high prevalence diseases, such as herpes, used the salivary glands as a reservoir. This may help explain why SARS-CoV-2 is so infectious,” Bruno Fernandes Matuck, doctoral student at USP’s School of Dentistry and lead author of the study, told FAPESP.
In an earlier study, researchers had demonstrated the presence of SARS-CoV-2 RNA in the periodontal tissue of patients who died from Covid-19.
Because of SARS-CoV-2’s high infectivity when compared to other respiratory viruses, they suggested that the novel coronavirus could infect and replicate in salivary gland cells and thus emerge in saliva with no contact with nasal and lung secretions.
Earlier international studies have shown that the salivary duct bears the ACE-2 receptor, with which the spike protein of SARS-CoV-2 binds to infect cells. More recently, other groups of scientists have reported that they have observed in animal studies that, in addition to ACE2, receptors such as transmembrane serine protease 2 (TMPRSS) and furin, which are present in salivary gland tissues, are targets for SARS-CoV-2.
Source: Exame