Salivary glands are a target for SARS‐CoV‐2: a source for saliva contamination

Abstract

The ability of the new coronavirus SARS‐CoV‐2 to spread and contaminate is one of the determinants of the COVID‐19 pandemic status. SARS‐CoV‐2 has been detected in saliva consistently, with similar sensitivity to that observed in nasopharyngeal swabs. We conducted ultrasound‐guided postmortem biopsies in COVID‐19 fatal cases. Samples of salivary glands (SGs; parotid, submandibular, and minor) were obtained. We analyzed samples using RT‐qPCR, immunohistochemistry, electron microscopy, and histopathological analysis to identify SARS‐CoV‐2 and elucidate qualitative and quantitative viral profiles in salivary glands. The study included 13 female and 11 male patients, with a mean age of 53.12 years (range 8–83 years). RT‐qPCR for SARS‐CoV‐2 was positive in 30 SG samples from 18 patients (60% of total SG samples and 75% of all cases). Ultrastructural analyses showed spherical 70–100 nm viral particles, consistent in size and shape with the Coronaviridae family, in the ductal lining cell cytoplasm, acinar cells, and ductal lumen of SGs. There was also degeneration of organelles in infected cells and the presence of a cluster of nucleocapsids, which suggests viral replication in SG cells. Qualitative histopathological analysis showed morphologic alterations in the duct lining epithelium characterized by cytoplasmic and nuclear vacuolization, as well as nuclear pleomorphism. Acinar cells showed degenerative changes of the zymogen granules and enlarged nuclei. Ductal epithelium and serous acinar cells showed intense expression of ACE2 and TMPRSS receptors. An anti‐SARS‐CoV‐2 antibody was positive in 8 (53%) of the 15 tested cases in duct lining epithelial cells and acinar cells of major SGs. Only two minor salivary glands were positive for SARS‐CoV‐2 by immunohistochemistry. Salivary glands are a reservoir for SARS‐CoV‐2 and provide a pathophysiological background for studies that indicate the use of saliva as a diagnostic method for COVID‐19 and highlight this biological fluid's role in spreading the disease. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Detection of SARS-CoV-2 in the community by nucleic acid amplification testing of saliva

“…Results obtained with this study agree with other studies that have ascertained that soon after infection SARS-CoV-2 is abundantly detected in saliva (Pan et al, 2020;Zhu et al, 2020), in line with evidence that indicates that the epithelium associated with the salivary glands is an early site of virus replication (Huang et al, 2021;Matuck et al, 2021;Pascolo et al, 2020).…”

Ultrasound-Guided Minimally Invasive Tissue Sampling: A Minimally Invasive Autopsy Strategy During the COVID-19 Pandemic in Brazil, 2020

“…US-guided MITS also allowed us to assess the invasive potential of SARS-CoV-2, with the detection of the virus in various tissues, such as the heart [ 17 , 37 ], intestine and brain [ 17 ], periodontal tissue [ 38 ], and major and minor salivary glands [ 39 ]. These findings have an impact both on the identification of possible viral reservoirs and on understanding the pathophysiology of distinct clinical manifestations.…”

Population-based virucidal phthalocyanine gargle/rinse protocol to reduce the risk of coronavirus disease-2019: a community trial

“…The presence of SARS-CoV-2 in saliva causes viral proliferation and consequent RNA secretion in any cells involved in the production of salivary components, such as salivary glands, respiratory tract cells, and the periodontal tissue. [27][28] Although our research did not analyze the salivary components and substantivity, we observed a difference in COVID-19 risk in the test community compared to the control community. This was supported by the nding that the virus has been consistently detected in saliva; thus, the oral cavity was a source of SARS-CoV-2.…”