If not, as many experts say, then why do news reports also include “the mouth” as a site for where the virus can enter the body? In the npr report where experts weighed in on this topic, one of them said that it is an upper respiratory tract illness and eating food contaminated by it isn’t how it’s transmitted. So which is it?
Mucus membranes in your mouth. You can breathe through your mouth.
Not your stomach.
From the article: “William Schaffner explains that the virus is primarily risky to us when it attaches to surfaces in our respiratory tract, not when we accidentally eat it. “The virus seems to be latching onto cells in the upper reaches of the nose, a place food doesn’t enter,” he explains. “Virus that found its way into your gastrointestinal tract would be killed by the acid in your stomach.””
What’s the difference between the virus getting into your mouth via food vs. fingers? Why do doctors say “don’t touch your mouth”. Or is that just bad reporting?
The SARS-Cov-2 virus likes to colonize in the lower respiratory tract and the lungs. While it is not inconceivable that you could contract it through the oral consumption route (since aerosols coming off the food, which is what gives it taste and smell, could be inhaled) it seems unlikely that it would get an infection through ingestion, though you would actually need to perform controlled animal studies to verify that. It also appears that the virus breaks down with heat and humidity, so it would be expected that either direct heat (roasting, baking, frying) or indirect heat (steaming, microwave) would deactivate the virus. Unlike viruses such as the dread norovirus (which despite often being dismissed as “just food poisoning” kills around 200k people a year) it does not transfer through the fecal-oral or vomit-oral route. However, you do inhale and exhale through the mouth, so of course both the nose and mouth should be covered if you are seeking to prevent transmission either from or to someone else.
FWIW, the MERS-CoV virus, which is another coronavirus of the same genus (betacoronavirus) but of a different lineage (Merbecovirus, where the SARS viruses are of lineage Sarbecovirus) was found to not be transmitted via food contamination. That is not definitive but they all use a similar spike glycoprotein which seems to target the respiratory system in humans. Most viruses tend to be particular about the cells they prefer to invade (referred to as host tropism) and do not easily transfer through other routes. Viral hemorrhagic fevers (VHF) like Ebola, Marburg, and Dengue fever tend to be amphotropic (can infect a wide range of cells) which means many parts of the body, including major organs needed to sustain life functions and fight infection, are all under attack at the same time which is why they can be so lethal and gruesome in their effects.
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So why is touching your mouth cautioned against? I imagine if your hands were covered with virus and you touched your mouth’ the virus would stick to saliva and mucous in your mouth, just as with food, not sponaneously aerosolize. Most people aren’t mouth breathers. What’s so special about fingers touching your mouth vs contaminated food?
First of all, despite the pejorative connotation of the term, everybody is a “mouth breather”. Unless you walk around with your mouth constantly sealed and never talking, you breath through your mouth. And when you inhale air through your mouth, you naturally pull small globules of fluid into your respiratory tract. You also expel fluid when you exhale, as anyone who has woken up in a poorly ventilated tent on a cold night can attest to.
Cooked food that has not been touched or breathed upon by an infected person most likely does not contain a significant amount of virus when it comes out of the pan or the stove. Where you generally see transmission of viral pathogens in food is in undercooked food or post-cook handling (e.g. food sitting around in bins with someone coughing or handling without gloves). Raw or cold food is more likely to carry pathogens, so I would avoid sushi and salad as a takeout meal (for the duration, and in general unless you are confident in the preparation) but with cooked prepared food you are most likely to be exposed to SARS-CoV-2 (or any number of other viral or bacterial pathogens that are always in circulation) via the packaging, enclosed packets of sauce, or just from handing your credit card or cash over and getting change.
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Starting in late March / early April, I began to see articles suggesting that covid-19 could infect the digestive tract, producing gastro symptoms including nausea, vomiting, and diarrhea. These could be present along with, or without, the usual respiratory symptoms.
Google covid-19 digestive route, for example, to find a bunch of cites. Here’s one.
ETA: Here’s another example:
Some COVID-19 Patients Present With GI Symptoms Only