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The Stomach Bug

February 27, 2024

The “Stomach Bug” is cursing many households right now.  Here is our website article on how to manage vomiting and diarrhea symptoms, and directions on when to seek care.

Here is some great information from Immunologic (immunologic@substack.com) about this nasty infection:

Noroviruses are the most common cause of acute gastroenteritis (inflammation of the Gl tract). Norovirus outbreaks can occur throughout the year, but are most common during winter: which means, right now! Currently, norovirus test positivity rates are between 12 and 13%, with case rates especially high in the northeast. This is not quite as high as the rates this time last year, which peaked at around 15%.

While sometimes called “stomach flu”, norovirus is not remotely related to influenza viruses. Noroviruses are in the calicivirus family, which are non-enveloped viruses. Non-enveloped, or naked viruses like noroviruses tend to be more virulent than enveloped viruses. This is because they are more resistant to the elements and can withstand heat, humidity changes, and many disinfectants.

Most hand sanitizers are ineffective at inactivating non-enveloped viruses like noroviruses

Alcohol-based hand sanitizers work to inactivate viruses by a few mechanisms, based on the active ingredient: either ethanol or isopropanol (2 different alcohols).

Most commercial hand sanitizers range between 40-80% alcohol content. For effective inactivation of norovirus (and other non-enveloped viruses), you need 95% ethanol. As such, hand washing with soap and water is the preferred method for proper hygiene among the general public, especially if you’ve been in contact with fecal matter.

Detergents in soap form micelles (think of these like little fat cages) around pathogens which trap them and allow them to be washed away when rinsing with water.

What about cleaning surfaces?

Don’t panic – there are some chemicals that are effective for disinfecting surfaces that may be contaminated with norovirus:

Bleach (Sodium Hypochlorite): Bleach is your number one option and is the most effective disinfectants against norovirus. Bleach works by denaturing proteins and disrupting viral RNA, much more effectively than alcohol. A solution containing 5-25 tablespoons of household bleach per gallon of water is recommended. The exact concentration may vary based on the surface and situation.

Other options if bleach isn’t available:

1.    Hydrogen Peroxide: Hydrogen peroxide at a concentration of at least 3% can be effective against norovirus. It acts as an oxidizing agent, damaging essential components of the virus.

2.    Quaternary Ammonium Compounds: Also known as “quats,” these compounds can be found in household cleaning products and some types of disinfectant wipes. They can be effective against norovirus but often need to be used at higher concentrations. (Note: this includes benzalkonium chloride, which is not as effective as bleach and requires longer contact time and higher concentration).

3.    Alcohols at Higher Concentrations: While regular alcohol-based hand sanitizers are not very effective against norovirus, higher concentrations of alcohol in certain disinfectants (95%) can have some efficacy. However, their use is more limited compared to other options like bleach.

If you aren’t sure what you have is effective, check the EPA list of antimicrobials for norovirus.

Norovirus is also extremely contagious.

Someone can get infected after being exposed to fewer than 20 viral particles. That’s why it spreads phenomenally easily through person-to-person contact, fecal-oral, contaminated surfaces, and food/water sources (such as shellfish harvested from contaminated areas.)

Another fun tidbit: you can shed virus in your stool for several weeks after symptoms disappear, and since it spreads so easily and the virus is so stable, it means that infections can rage in communities.

Illness caused by norovirus is fast and furious

Symptoms develop between 12 and 48 hours after exposure and are typically violent. They include nausea, acute-onset vomiting, watery, non-bloody diarrhea, and abdominal cramps. Fatigue, muscle aches, headache, and fever can also be present.

Now, for all you reading and thinking, jeez, what next?! There is some good news. Illness for most is usually mild, & symptoms last 1-3 days. However, norovirus can be particularly serious for young children and older adults.

How can you protect yourself and others if someone at home has norovirus?

Unfortunately, there is no vaccine for norovirus and treatment involves supportive care. But if someone at home has norovirus, it isn’t a guarantee that everyone else will get it. You can take steps to reduce the risk.

Hand hygiene, especially in any common areas and particularly in the bathroom and kitchen spaces. Soap and water is king here. This is especially important after using the toilet, after changing diapers (if applicable), and before eating, preparing, or handling food.

Food hygiene is essential. It goes without saying the sick individual should not be touching common food or prepping food for others in the house, and, if possible, should not be in the vicinity when food is being prepared. You should also not prepare foods for up to 3 days after your symptoms subside. However, additional measures can also be taken. Thoroughly wash fruits and vegetables before preparing and eating them, especially if eaten raw. Ensure seafood is washed and cooked thoroughly: norovirus can survive “searing” and quick “steaming” and temperatures up to 140F. Any foods that are potentially contaminated from the sick individual should be discarded. You can also consider wearing clean gloves while handling food or interacting with a sick individual.

Disinfect surfaces immediately. Any surfaces which have been in contact with vomit or fecal matter should be disinfected as soon as possible. Use a chlorine bleach solution with a concentration of 1000–5000 ppm (5–25 tablespoons of household bleach [5.25%] per gallon of water).

Thorough and prompt laundry. Anything: clothing, linens, etc., that may be contaminated should be washed. Minimize disturbance of potentially contaminated fabrics (remember: 20 viral particles can infect someone), wear gloves while handling and wash hands thoroughly after touching. Wash items in the washing machine with the highest cycle length and machine dry (for additional heat sterilization) afterward.

Caring for the sick individual. If the individual is actively vomiting, having diarrhea, and may not have the best hygiene for whatever reason, you can consider wearing a high quality mask around the house when you are in contact with them. This will reduce the likelihood of particles floating around that may contain virus. You can also consider wearing gloves if providing care for them, and always make sure to wash your hands extra thoroughly after interacting with them. You may also consider changing out of clothing you wore when in contact with them so you aren’t potentially carrying viral particles elsewhere around the house or out of the house.