Norovirus: The real “stomach flu”
© 2016 Roy Benaroch, MD
Informally, it’s sometimes mistakenly called “the stomach flu” or “a tummy bug”—an illness with some aches and fevers, but mostly vomiting and diarrhea, that often occurs in mini-epidemics in households, daycares, and schools. One kid gets it, and the rest of the dominoes fall, in a most unpleasant and stinky manner.
The illness has nothing at all to do with influenza, by the way. Influenza is a respiratory virus, spread by mucus, that mainly causes aches and fever, along with cough and sometimes some vomiting or abdominal pain. Influenza cases are concentrated during a few months of winter, and there’s a vaccine that can prevent at least some cases.
The “stomach flu” isn’t a flu at all. Technically, we call it an “acute gastroenteritis”, with inflammation of the stomach and intestines, sometimes shortened to just a “gastro” or “AGE”. These days, the most common cause, year-round, is a nasty and clever little virus called “norovirus”, or “noro” for short. (Docs are always in a hurry. We prefer short words.)
Here’s a lovely thought: volunteers who touched a surface smeared with 30 microliters of infected feces—that’s about half of a drop—all got enough virus on their hands to potentially make them sick. And, get this, if they then touched a doorknob or telephone or another surface, that would transfer enough virus to get the next person sick. In fact, 10 people in a row, serially touching surfaces one after another, would all potentially get sick after the first person touched that first surface, with half a drop of stool. Seriously. Someone did this experiment.
The incubation period between contact with the virus and symptoms is 12-48 hours, though people who are becoming sick become contagious before symptoms start. Though the illness itself is usually brief, typically lasting only a few days, virus continues to be shed in the stool for several weeks, and maybe at low levels for even longer. Both vomit and diarrhea can be loaded with infectious viral particles – and it’s so contagious that documented transmission has occurred in people just walking through an emergency department near someone who has been vomiting.
There is some good news. The virus itself cannot make you sick if it just gets on your skin. It has to invade your body through a “mucus membrane,” like your mouth or nose or eyes (this is true of almost all infectious, by the way—they need a break in the skin barrier or a wet membrane to get through). So as long as you wash your hands well before you eat or drink or touch your face, you ought to be OK.
“Wash your hands well” – that’s not so easy. A CDC-recommended decontamination handwash is 60 seconds of rubbing with soapy water, a 20 second rinse, and drying with disposable paper towels. Do that before and after every patient (as every health care worker should), and by the end of the day your hands will be bloody cracked dry stumps (OK, maybe it’s not that bad. But my knuckles get pretty raw. I know, boo hoo me.) Hand sanitizers containing 70% alcohol help, some, though they’re no substitute for full-on soapy water hand washes.
If vomiting and diarrhea does strike your children, here’s what you ought to do:
- Keep them home. Please, please keep them home.
- Wash hands well, and wash hands frequently.
- Decontaminate surfaces with diluted bleach. Standard detergent sprays help, but bleach is da bomb.
- Offer frequent, small sips of fluids. They don’t have to eat (and don’t make ‘em eat if they don’t want to), but continued fluid intake is essential.
- Seek medical attention if your child shows signs of significant dehydration, especially listlessness, an inability to drink, or very little urine output.