SARS-CoV-2 infects mouth cells

Researchers have recently found evidence that SARS-CoV-2 infects cells in the mouth, especially salivary glands and tissues in the oral cavity. This suggests that SARS-CoV-2 is a potential infection and site of infection.

The upper respiratory tract and lungs are known to be infected sites of the virus that causes COVID-19, but these latest discoveries explain a wide range of disease-related symptoms and methods, including loss of taste and odor. It may be. The virus infects the lungs and digestive tract through saliva, the researchers said.

In addition, “These findings are Avoid crowds Wearing a mask to prevent SARS-CoV-2 infection ” Blake M. Warner, DDS, PhD, MPH, AN An assistant clinical researcher at the National Institute of Dental and Craniofacial Research and head of the Salivary Gland Disorders Unit told Healtho Primary Care.

Studies have confirmed that saliva may contain high levels of SARS-CoV-2 — Enough for diagnostic tests —But according to Warner, the question remains where the virus in saliva comes from, especially in people without respiratory symptoms.

To investigate the possibility that the virus may come from infected tissue in the mouth, Warner and colleagues studied oral tissue from healthy people. They identified RNAs of two invading proteins that allow the virus to invade salivary glands and, to a lesser extent, cells in the mucosa (ACE2 receptor and TMPRSS2 enzyme).

“The expression level of the invading factor is similar to the expression level of areas known to be susceptible to SARS-CoV-2 infection, such as the tissue covering the nasal passages of the upper respiratory tract,” Warner said in a press release. I explained in.

After determining that certain parts of the mouth were susceptible to infection, researchers looked for evidence of infection in oral tissue samples taken from patients with COVID-19. They said SARS-CoV-2 RNA was present in more than half of the tissue samples taken from deceased patients. In salivary gland tissue samples from one dead person and another living patient with COVID-19, researchers found evidence that cells were actively making new copies of the virus, indicating infection. ..

Researchers found that cells released into saliva from the mouth of patients with mild or asymptomatic disease contained SARS-CoV-2 RNA in addition to the invasive protein RNA, and found that the oral cavity He said he showed that the tissue was the source of the virus. In saliva.

Next, according to a press release, researchers exposed the saliva of eight asymptomatic COVID-19 patients to healthy, dish-grown cells. The saliva of two volunteers infected healthy cells. This suggests that even people who are asymptomatic of COVID-19 can infect others with the infectious virus through saliva.

According to the release, researchers also collected saliva from another group of 35 people with asymptomatic or mild COVID-19. Of the 27 people who experienced symptoms, those who were found to contain the virus in saliva were more likely to report loss of taste and smell, possibly explaining the oral symptoms of COVID-19. there is.

“Our results not only show the relationship between the reported symptoms, taste and smell loss and the presence of the virus in saliva, but also SARS-CoV-2 in saliva is responsible for the spread. It also shows the possibility. In the body, swallowed infectious particles can spread to the intestines and lungs, and can be directly involved in infecting others through the large droplets that are excreted. ” He said in an interview with Healio.

According to Warner, the next step is to analyze additional oral tissue types, such as the tongue and tonsils. Doing so creates a “comprehensive roadmap for cell-type-specific viral vulnerabilities” against SARS-CoV-2 and other viruses (both known and novel) in the oral cavity, preparing for future pandemics. And “preventive or therapeutic intervention.”

reference:

NIH (National Institutes of Health. Scientists have found evidence that the new coronavirus infects cells in the mouth. March 25, 2021. https://www.nih.gov/news-events/news-releases/scientists-find-evidence-novel-coronavirus-infects-mouths-cells.. Accessed on March 31, 2021.

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