It was previously known that the upper respiratory tract and lungs are the main foci of SARS-CoV-2 infection.
The fact that the virus can infect multiple areas of the body may help explain the wide range of symptoms experienced by COVID-19 patients.
Moreover, the findings indicate that the mouth may play a role in the transmission of SARS-CoV-2 to the lungs or digestive system through virus-laden saliva.
Researchers examined oral tissue in healthy people to identify areas of the mouth susceptible to SARS-CoV-2 infection.
RNA of two key proteins for penetration - the ACE2 receptor and the TMPRSS2 enzyme - was found in salivary gland cells and oral tissues. This indicates increased vulnerability, since the virus is thought to require both input proteins to gain access to cells.
In addition, in the tissue of the salivary glands of one ofdead people, as well as a person who is currently suffering from an acute form of COVID-19, scientists discovered specific sequences of viral RNA: they indicated that the cells were actively making new copies of the virus.
More research will be needed toconfirm the findings in a larger group of people and determine the exact nature of how our mouths spread SARS-CoV-2 and transmit it outside the body.
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