Journal Article

Direct detection of SARS-CoV-2 antisense and sense genomic RNA in human saliva by semi-autonomous fluorescence in situ hybridization: A proxy for contagiousness?

van Wamel, Willem J. B., Wijnberg, Inge D., Wiersma, Marit, Jansen, Gijsbert J.

2021

Overview

Saliva is a matrix which may act as a vector for pathogen transmission and may serve as a possible proxy for SARS-CoV-2 contagiousness. Therefore, the possibility of detection of intracellular SARS-CoV-2 in saliva by means of fluorescence in situ hybridization is tested, utilizing probes targeting the antisense or sense genomic RNA of SARS-CoV-2. This method was applied in a pilot study with saliva samples collected from healthy persons and those presenting with mild or moderate COVID-19 symptoms. In all participants, saliva appeared a suitable matrix for the detection of SARS-CoV-2. Among the healthy, mild COVID-19-symptomatic and moderate COVID-19-symptomatic persons, 0%, 90% and 100% tested positive for SARS-CoV-2, respectively. Moreover, the procedure allows for simultaneous measurement of viral load (‘presence’, sense genomic SARS-CoV-2 RNA) and viral replication (‘activity’, antisense genomic SARS-CoV-2 RNA) and may yield qualitative results. In addition, the visualization of DNA in the cells in saliva provides an additional cytological context to the validity and interpretability of the test results. The method described in this pilot study may be a valuable diagnostic tool for detection of SARS-CoV-2, distinguishing between ‘presence’ (viral load) and ‘activity’ (viral replication) of the virus. Moreover, the method potentially gives more information about possible contagiousness.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Analysis / Antigens / Antisense RNA / Biology and life sciences / Case-Control Studies / Coronaviruses / COVID-19 / COVID-19 - diagnosis / COVID-19 - pathology / COVID-19 - virology / Deoxyribonucleic acid / Disease transmission / DNA / DNA probes / Fluorescence / Fluorescence in situ hybridization / Genomics / Humans / Hybridization / Immunoglobulins / In Situ Hybridization, Fluorescence - methods / Infectious diseases / Mathematical analysis / Medical research / Medicine and health sciences / Pandemics / Pathogens / Replication / Research and Analysis Methods / Ribonucleic acid / RNA / RNA, Antisense - genetics / RNA, Antisense - metabolism / RNA, Viral - analysis / RNA, Viral - genetics / RNA, Viral - metabolism / Saliva / Saliva - virology / SARS-CoV-2 - genetics / SARS-CoV-2 - isolation & purification / SARS-CoV-2 - physiology / Severe acute respiratory syndrome / Severe acute respiratory syndrome coronavirus 2 / Severity of Illness Index / Viral diseases / Viral Load / Virus Replication / Viruses