(Source CNN)

With covid-19 continuing to rage on we keep learning more about the virus and specifically how it spreads. As researchers continue to try and understand the virus, they have provided some explanation for people who test negative even though they experience symptoms.

“Researchers say they have found evidence that coronavirus infects the mouth, including inside the cheeks, in the gums and in salivary glands. When people swallow infected saliva, they could be spreading the virus to other parts of their bodies”, CNN’s Maggie Fox states.

The study, detailed in the journal Nature Medicine on Thursday, may explain why so many people infected lose their sense of taste, and suggests the mouth is an important source of the spread of Covid-19. It was previously known that saliva testing was a good way to detect infection,but researchers hadn’t looked to see why. This is what may have caused it to infect the individual further.

“When infected saliva is swallowed or tiny particles of it are inhaled, we think it can potentially transmit SARS-CoV-2 further into our throats, our lungs, or even our guts,” said Dr. Kevin Byrd of the American Dental Association Science and Research Institute, who worked on the study.

This is what causes various symptoms as the infected saliva travels to certain areas like the gut, For instance Mucus drain travels down the throat causing the spread to the stomach which is why it may only attack that particular area of the body over the others. The same can be said for the respiratory system.

The mouth, nose, sinuses, throat and lungs are connected, and the virus can spread across all those regions in the mucus that drains or is coughed up. They checked samples of oral tissue from people who died of Covid-19 and found the virus in about half of the salivary glands they tested.

The study also found evidence that people who test negative after a nasal swab sometimes continue to test positive on a saliva test, highlighting that even if the virus is cleared from the nasopharynx — the upper part of the throat behind the nose — it could persist in saliva.