Microscopic observations of SARS-CoV-2 like particles in different oral samples

Area of Science:

• Oral Medicine
• Virology
• Microscopy

Background:

• The transmission routes of SARS-CoV-2, the virus causing COVID-19, are primarily airborne.
• The role of the oral cavity in SARS-CoV-2 infection and transmission remains unclear.
• Previous studies detected viral RNA in oral samples, hinting at saliva's involvement.

Purpose of the Study:

• To investigate the presence of SARS-CoV-2 particles in oral samples from symptomatic COVID-19 patients.
• To determine if the oral cavity serves as a site for SARS-CoV-2 replication.

Main Methods:

• Scanning electron microscopy (SEM) was used to visualize viral particles.
• Correlative light and electron microscopy provided detailed imaging.
• Immunofluorescence staining confirmed viral presence.
• RT-qPCR detected SARS-CoV-2 RNA in saliva, dental plaque, and gingival crevicular fluid (GCF).

Main Results:

• SARS-like particles were identified in RT-qPCR positive saliva, dental plaque, and GCF samples.
• Oral epithelial cells in saliva exhibited features consistent with SARS-CoV-2 infection.
• Vacuoles containing nascent viral particles were observed within infected oral cells, indicating replication.

Conclusions:

• The oral cavity can harbor SARS-CoV-2.
• Evidence suggests SARS-CoV-2 can infect and replicate within oral tissues.
• The oral cavity may act as a reservoir for the virus and contribute to its transmission.